Existing law prohibits the maximum gross weight on any one axle of a bus from exceeding 20,500 pounds, except the maximum limit for the curb weight on any one axle of a transit bus procured through a solicitation process pursuant to which a solicitation was issued on or after January 1, 2019, is set at 22,000 pounds. Existing law, notwithstanding the previous provisions, sets specified higher maximum limits up to 25,000 pounds for the curb weight on any one axle of an articulated transit bus or zero-emission transit bus procured through a solicitation process pursuant to which a solicitation was issued during specified periods between January 1, 2016, and December 31, 2021, inclusive, and sets the 22,000-pound maximum limit for an articulated transit bus or zero-emission transit bus procured through a solicitation process pursuant to which a solicitation was issued on or after January 1, 2022. A violation of this provision is a crime.

This bill would, until January 1, 2032, establish specified higher weight limitations up to 25,000 pounds for zero-emission transit buses procured through a solicitation process pursuant to which a solicitation was issued at various specified periods between January 1, 2027, and December 31, 2031 inclusive.

Existing law prohibits the maximum gross weight on any one axle of a bus from exceeding 20,500 pounds, except the maximum limit for the curb weight on any one axle of a transit bus procured through a solicitation process pursuant to which a solicitation was issued on or after January 1, 2019, is set at 22,000 pounds. Existing law, notwithstanding the previous provisions, sets specified higher maximum limits up to 25,000 pounds for the curb weight on any one axle of an articulated transit bus or zero-emission transit bus procured through a solicitation process pursuant to which a solicitation was issued during specified periods between January 1, 2016, and December 31, 2021, inclusive, and sets the 22,000-pound maximum limit for an articulated transit bus or zero-emission transit bus procured through a solicitation process pursuant to which a solicitation was issued on or after January 1, 2022. A violation of this provision is a crime.

This bill would, until January 1, 2032, establish specified higher weight limitations up to 25,000 pounds for zero-emission transit buses procured through a solicitation process pursuant to which a solicitation was issued at various specified periods between January 1, 2027, and December 31, 2031 inclusive.

Existing law prohibits the maximum gross weight on any one axle of a bus from exceeding 20,500 pounds, except the maximum limit for the curb weight on any one axle of a transit bus procured through a solicitation process pursuant to which a solicitation was issued on or after January 1, 2019, is set at 22,000 pounds. Existing law, notwithstanding the previous provisions, sets specified higher maximum limits up to 25,000 pounds for the curb weight on any one axle of an articulated transit bus or zero-emission transit bus procured through a solicitation process pursuant to which a solicitation was issued during specified periods between January 1, 2016, and December 31, 2021, inclusive, and sets the 22,000-pound maximum limit for an articulated transit bus or zero-emission transit bus procured through a solicitation process pursuant to which a solicitation was issued on or after January 1, 2022. A violation of this provision is a crime.

This bill would, until January 1, 2032, establish specified higher weight limitations up to 25,000 pounds for zero-emission transit buses procured through a solicitation process pursuant to which a solicitation was issued at various specified periods between January 1, 2027, and December 31, 2031 inclusive.

 THIRD READING  

Bill No: AB 1944

Author: Lee (D)

Introduced: 2/13/26

Vote: 21

SENATE TRANSPORTATION COMMITTEE: 10-3, 6/9/26

AYES: Cortese, Archuleta, Arreguín, Blakespear, Gonzalez, Grayson, Menjivar, Richardson, Valladares, Wiener

NOES: Strickland, Dahle, Seyarto

ASSEMBLY FLOOR: 62-3, 4/6/26 - See last page for vote

SUBJECT: Zero-emission transit buses: axle weight

SOURCE: California Transit Association

DIGEST:

This bill establishes higher axle weight limits for zero-emission transit buses, up to 25,000 pounds through 2027, with limits decreasing to 22,000 pounds by 2032.

ANALYSIS:

Existing law:

1. Establishes a maximum curb weight, as defined, of 22,000 pounds on any one axle of a bus procured through a solicitation process where the solicitation was issued on or after January 1, 2019. (Vehicle Code Section 35554(c)(2))
2. Establishes a decreasing maximum curb weight, as defined, on any one axle of a zero-emission transit bus of 25,000 pounds starting January 1, 2016, to 22,000 pounds by January 1, 2022. (Vehicle Code Section 35554(d)(1))

This bill:

1. Extends the dates by which zero-emission transit buses must reach target, maximum curb weights, as follows:
   1. Establishes a maximum curb weight of 25,000 pounds on any one axle for zero-emission buses procured through a solicitation process where the solicitation was issued between January 1, 2027, and December 31, 2027, inclusive.
   2. Establishes a maximum curb weight of 24,000 pounds on any one axle for zero-emission buses procured through a solicitation process where the solicitation was issued between January 1, 2028, and December 31, 2029, inclusive.
   3. Establishes a maximum curb weight of 23,000 pounds on any one axle for zero-emission buses procured through a solicitation process where the solicitation was issued between January 1, 2030, and December 31, 2031, inclusive.
   4. Establishes a maximum curb weight of 22,000 pounds on any one axle for zero-emission buses procured through a solicitation process where the solicitation was issued on or after January 1, 2023.

Comments

1. Purpose of the bill. According to the author, “California has set ambitious zero-emission goals, requiring that by 2029 all buses purchased by transit agencies must be zero-emission vehicles. However, because of axle-weight limits set by the Legislature, transit agencies are struggling to procure Zero Emission Busses that keep up with their operational needs while staying within existing weight limits. AB 1944 provides a practical and responsible solution by adjusting the timeline for these limits while maintaining the previously negotiated upper weight cap, allowing California Transit Agencies to continue making progress towards our clean transportation goals.”
   
2. Innovative Clean Transit regulation. In December 2018, as part of its efforts to regulate vehicle emissions, the California Air Resources Board (CARB) adopted the Innovative Clean Transit (ICT) regulation. ICT is a statewide rule that requires public transit agencies to transition their bus fleets to zero-emission vehicles. Specifically, the ICT sets up two different timelines for large and small transit agencies. A large transit agency is defined as (1) any transit agency in the South Coast or San Joaquin Valley Air Basin that operates more than 65 buses in annual maximum service, or (2) any transit agency outside of these areas, but in an urbanized area with a population of at least 200,000 that operates at least 100 buses in annual maximum service. A small transit agency is any agency that does not meet either of these definitions.
   Under the ICT, large transit agencies are required to have 25% of their bus purchases in each calendar year be zero-emission starting on January 1, 2023, 50% be zero-emission starting on January 1, 2026, and 100% be zero-emission starting on January 1, 2029. Small transit agencies are required to have 25% of their bus purchases in each calendar year be zero-emission starting on January 1, 2026, and 100% be zero-emission starting on January 1, 2029. All transit agencies are required to fully transition all of their buses to zero-emission by 2040.
   
3. Heavy buses damage roads. As vehicles drive over roads, they exert pressure, causing wear, and thus damaging road surfaces over time. The amount of damage is proportional to the weight of the vehicle; however, this relationship is not linear. Instead, broadly speaking, road wear is generally thought of as being proportional to a vehicle’s axel weight to the fourth power. This means that doubling the weight of a vehicle can increase damage to the road by 16 times. Large vehicles, like trucks or transit buses, can weigh up to 20 times more than an average passenger vehicle, causing substantially more road wear than a typical passenger vehicle.
   
   Thus, in order to mitigate these effects, large vehicles have maximum weight loads. Current California law limits buses to a single axle weight of 20,500 pounds. However, numerous exceptions have been made over time, including for transit buses and zero-emission buses. As of today, the maximum allowed single axle weight for a zero-emission transit bus is 22,000 pounds.
   
4. Zero-emission bus availability. Currently, many zero-emission bus options are available to transit agencies across California, including both battery electric and hydrogen fuel cell options. However, these buses are not one-to-one replacements for the traditional buses currently used by transit agencies in terms of cost or performance. As a result, transit agencies are struggling to comply with the latest phase of ICT rules.
   
   These issues were highlighted in CARB’s comprehensive review of the ICT regulation ahead of the Phase II transition in 2026. This review was carried out before the 2026 rules came into effect in order to assess the readiness of transit agencies to conform with the regulations. Overall, while the report found that the market was generally able to support the required transitions to zero‑emission buses, there were key exceptions. Namely, the report identified issues surrounding a lack of necessary infrastructure and associated high costs with infrastructure deployment, and a lack of longer-range bus models.
   As a result, transit agencies do not have access to zero-emission buses with the range necessary to comparably replace their current fleets. Generally speaking, transit buses need a range of up to 300 miles, with additional margin to account for weather conditions, terrain, running HVAC systems, and battery degradation overtime. Presently, however, zero-emission buses available to California transit operators have ranges maxing out at roughly 250 miles.
   
   In order to increase bus ranges, bus manufacturers need to add additional battery capacity which in turn increases the weight. Current models, with lower ranges, are already at the statutory axle weight maximum in California. Therefore, according to the author, some kind of exemption is needed to allow bus manufacturers to find ways to increase range without substantially increasing weight.
   
   Beyond the weight issues, cost is also a concern. A recent audit of East Bay Transit Agencies performed by the California State Auditor, found that the average zero-emission bus costs roughly twice as much as the average diesel bus. Multiplying this cost across the various agencies’ fleet sizes, the audit found that the costs generally far exceed agency revenues and reserves. Exacerbating factors further, the Federal Transit Administration has stopped awarding grants for purchasing zero-emission buses. As a result, the audit found that transit agencies will face difficulty meeting the ICT requirement and recommended that the Legislature extend the ICT deadline.
   
5. Creating axle weight exemptions, again. AB 1944 seeks to ease some of these burdens on transit operators by allowing them to operate heavier buses while industry works to catch up and supply buses compliant with ICT. Specifically, this bill extends the dates by which transit agencies must reduce the weights of their zero-emission buses, pushing out the ultimate deadline for meeting the 22,000 pound curb weight requirement to 2032.
   
   However, this is not the first-time limits on transit bus weights have had to be pushed off. AB 1706 (Eng, Chapter 771, Statutes of 2012) allowed transit operators to operate buses over the previously established 20,500 pound axle weight limit, and to procure further overweight buses through 2015. As the new 2015 deadline approached, AB 1720 (Bloom, Chapter 263, Statutes of 2014) provided an additional two-year exemption. Finally, AB 1250 (Bloom, Chapter 484, Statutes of 2015) aimed to address the issue in the longer term by creating a decreasing weight schedule that allowed articulated buses and zero-emission buses to slowly come into compliance with an increased 22,000 pound limit over a seven year period. This final deadline for 22,000 pounds was reached in 2022.
   
   As discussed above, however, this 22,000 pound limit is too restrictive to meet current needs. Currently, zero-emission bus manufacturers are attempting to offset weight increases associated with increased battery range by finding weight reductions in other areas throughout the bus. Manufacturers are counting on innovations in bus design and battery technology to reduce weights in time to meet the new deadlines for axle weight requirements put forward by this bill. However, absent a specific technological or design innovation, it is unclear if they will be able to do so, and thus this problem may reoccur in the future.
   
6. Local jurisdictions are concerned about road damage. While transit operators tout the need of a weight limit exemption, local jurisdictions, particularly cities, have raised concerns about increased road damage. Importantly, as roads deteriorate more, they become exponentially more expensive to repair, meaning relatively frequent resurfacing is cheaper than waiting to replace a pavement entirely once it has degraded too much. However, even these more modest repairs are out of reach for many jurisdictions, as in 2025 alone there was a $54.2 billion shortfall in needed funding for maintaining pavement. As a result, many local roads across the state are at risk of further degradation, requiring more expensive repairs, and widening the shortfall even further.
   
   For these reasons, local jurisdictions are concerned about allowing the operation of heavier transit buses. One potential solution floated by some local jurisdictions is to allow transit operators to utilize lower weight, low NOx buses while waiting for advancements in zero-emission bus technology. While this would address the bus weight issue, it would violate and effectively nullify the ICT requirements by allowing the operation of GHG emitting buses. Ultimately, the Legislature should consider whether it wants to maintain the status quo, minimize road damage at the cost of increased transit emissions, or accept heavier buses and thus increased road wear in exchange for zero-emission transit buses.

FISCAL EFFECT: Appropriation: No Fiscal Com.: No Local: No

SUPPORT: (Verified 6/9/2026)

California Transit Association (Source)

Alameda-Contra Costa Transit District
California Electric Transportation Coalition
Monterey-Salinas Transit
Orange County Transportation Authority
Sacramento Regional Transit District
San Diego Metropolitan Transit System
San Mateo County Transit District
Santa Clara Valley Transportation Authority
Santa Cruz Metropolitan Transit District
Sunline Transit Agency
Transportation Agency for Monterey County

OPPOSITION: (Verified 6/9/2026)

League of California Cities

ARGUMENTS IN SUPPORT: Writing as the sponsor of this bill, the California Transit Association states, “In December 2018, CARB adopted the ICT regulation, which requires public transit agencies to convert their bus fleets to zero-emission technology by no later than 2040. The regulation functions by way of a tiered zero-emission bus (ZEB) purchase mandate, which requires that, beginning in 2023, transit agencies purchase a fixed percentage of ZEBs with each bus procurement…As ZEB deployment continues to increase (and short-range ZEBs are deployed on available shorter routes), transit agencies will be required to procure ZEBs with extended ranges to complete longer routes and more aggressive duty cycles. With today’s technology, extended range ZEBs require additional batteries, which result in additional weight that meet or, in some cases, exceed the axle weight limits in current law.”

ARGUMENTS IN OPPOSITION: Writing in opposition, the League of California Cities states, “AB 1944 authorizes higher axle weight limits for transit vehicles, which, by well-established engineering principles, will accelerate pavement damage on city streets. At the same time, the state’s transportation funding system, heavily reliant on SB 1 (Beall, Chapter 5, Statutes of 2017), is projected by the Legislative Analyst’s Office to decline by billions of dollars over the coming decade as zero-emission vehicle adoption increases. Without a corresponding funding solution, this creates an unsustainable mismatch between infrastructure wear and available resources.”

ASSEMBLY FLOOR: 62-3, 4/6/26

AYES: Addis, Aguiar-Curry, Ahrens, Alanis, Alvarez, Arambula, Berman, Boerner, Bonta, Bryan, Calderon, Carrillo, Castillo, Chen, Connolly, Davies, DeMaio, Dixon, Elhawary, Ellis, Flora, Fong, Garcia, Gipson, Jeff Gonzalez, Mark González, Haney, Hart, Hoover, Irwin, Jackson, Kalra, Krell, Lee, Lowenthal, McKinnor, Nguyen, Ortega, Pacheco, Papan, Patel, Patterson, Pellerin, Petrie-Norris, Ramos, Ransom, Michelle Rodriguez, Rogers, Blanca Rubio, Sanchez, Schiavo, Sharp-Collins, Solache, Soria, Stefani, Ta, Wallis, Ward, Wicks, Wilson, Zbur, Rivas

NOES: Bains, Hadwick, Macedo

NO VOTE RECORDED: Ávila Farías, Bauer-Kahan, Bennett, Caloza, Gabriel, Gallagher, Harabedian, Johnson, Lackey, Muratsuchi, Quirk-Silva, Celeste Rodriguez, Schultz, Tangipa, Valencia

Prepared by: Samuel Myers / TRANS. / (916) 651-4121

6/10/26 16:58:15

**** END ****

SENATE COMMITTEE ON TRANSPORTATION

Senator Dave Cortese, Chair

2025 - 2026 Regular

Bill No: Hearing Date: 6/9/2026

SUBJECT:

DIGEST: This bill establishes higher axle weight limits for zero-emission transit buses, up to 25,000 pounds through 2027, with limits decreasing to 22,000 pounds by 2032.

ANALYSIS:

Existing federal law:

1. Requires transit projects and procurements supported by federal funds to meet certain requirements regarding the use of American vehicles and vehicle components. (49 USC 5323)
   
2. Prohibits federal funds from being used to purchase transit buses and other rolling stock from China, among other nations. (49 USC 5323)
   

Existing state law:

1. Establishes a maximum gross weight of 20,500 pounds for any single axle of a bus, except for buses obtained via any solicitation issued before January 1, 2016, and acquired before January 1, 2021. (VEH 35554(a))
   
2. Defines “curb weight” as the total weight of a fully loaded transit bus, including maximum fuel, oil, and coolant, and all equipment used in the normal operation of the bus, except without passengers or a driver. (VEH 35554(g))
   
3. Establishes a maximum curb weight of 23,000 pounds on any one axle of a transit bus procured through a solicitation process where the solicitation was issued between January 1, 2016, and December 31, 2018, inclusive. (VEH 35554(c)(1))
   
4. Establishes a maximum curb weight of 22,000 pounds on any one axle of a bus procured through a solicitation process where the solicitation was issued on or after January 1, 2019. (VEH 35554(c)(2))
   
5. Establishes a maximum curb weight of 25,000 pounds on any one axle of a zero-emission transit bus procured through a solicitation process where the solicitation was issued between January 1, 2016, and December 31, 2017, inclusive. (VEH 35554(d)(1))
   
6. Establishes a maximum curb weight of 24,000 pounds on any one axle of a zero-emission transit bus procured through a solicitation process where the solicitation was issued between January 1, 2018, and December 31, 2019, inclusive. (VEH 35554(d)(2))
   
7. Establishes a maximum curb weight of 23,000 pounds on any one axle of a zero-emission transit bus procured through a solicitation process where the solicitation was issued between January 1, 2020, and December 31, 2021, inclusive. (VEH 35554(d)(3))
   
8. Establishes a maximum curb weight of 22,000 pounds on any one axle of a zero-emission transit bus procured through a solicitation process where the solicitation was issued on or after January 1, 2022. (VEH 35554(d)(4))
   
9. Requires a transit operator operating an articulated transit bus to provide notice to all cities and counties in whose jurisdiction the bus will operate in the upcoming calendar year, identifying among other things, the weight of the articulated bus. (VEH 35554(f))

This bill:

1. Extends the dates by which zero-emission transit buses must reach target, maximum curb weights, as follows:
   
   1. Establishes a maximum curb weight of 25,000 pounds on any one axle for zero-emission buses procured through a solicitation process where the solicitation was issued between January 1, 2027, and December 31, 2027, inclusive.
      
   2. Establishes a maximum curb weight of 24,000 pounds on any one axle for zero-emission buses procured through a solicitation process where the solicitation was issued between January 1, 2028, and December 31, 2029, inclusive.
      
   3. Establishes a maximum curb weight of 23,000 pounds on any one axle for zero-emission buses procured through a solicitation process where the solicitation was issued between January 1, 2030, and December 31, 2031, inclusive.
      
   4. Establishes a maximum curb weight of 22,000 pounds on any one axle for zero-emission buses procured through a solicitation process where the solicitation was issued on or after January 1, 2023.

COMMENTS:

1. Purpose of the bill. According to the author, “California has set ambitious zero-emission goals, requiring that by 2029 all buses purchased by transit agencies must be zero-emission vehicles. However, because of axle-weight limits set by the Legislature, transit agencies are struggling to procure Zero Emission Busses that keep up with their operational needs while staying within existing weight limits. AB 1944 provides a practical and responsible solution by adjusting the timeline for these limits while maintaining the previously negotiated upper weight cap, allowing California Transit Agencies to continue making progress towards our clean transportation goals.”
   
2. Clean air goals in transportation. Over the past several decades both the state and federal government have passed numerous pieces of legislation and implemented numerous requirements aimed at cleaning up the air and reducing Greenhouse Gas (GHG) emissions. Federally, the Clean Air Act of 1970 instructs the U.S. Environmental Protection Agency (US EPA) to set primary National Ambient Air Quality Standards (NAAQS) to protect public health, and secondary NAAQS to protect plants, forests, crops and materials from damage due to exposure to six criteria air pollutants. These pollutants include: particulate matter, ozone, nitrogen oxides, sulfur oxides, carbon monoxide, and lead. Furthermore, states that fail to properly implement NAAQS can trigger penalties, including the withholding of federal highway funds.
   
   At the state level, the Legislature, through SB 32 (Pavley, Chapter 249, Statutes of 2016), set ambitious targets to reduce GHG emissions to 40% below the 1990 level by 2030 and to achieve carbon neutrality by 2045. In order to achieve these goals, the California Air Resources Board (CARB), has been given broad authority to regulate GHG emissions and air pollution throughout the state. As part of this authority, CARB is tasked with developing a scoping plan to detail how the state will achieve its GHG emissions reduction targets. CARB is also tasked with developing emission reductions strategies associated with meeting the state’s requirements under the Clean Air Act.
   
   To reach these goals, CARB has the authority to regulate emissions from mobile sources. Mobile sources of air pollution are vehicles or equipment that can be moved from place to place and emit pollutants as they operate. These sources include on-road vehicles like cars, trucks, and buses, as well as non‑road vehicles such as aircraft, construction equipment, and marine vessels. Mobile sources and the fossil fuels that power them are the largest contributors to the formation of ozone, GHG emissions, fine particulate matter, and toxic diesel particulate matter (DMP). Mobile sources in California are responsible for approximately 80% of smog-forming nitrogen oxide (NOx) emissions. They also represent about 50% of GHG emissions when including emissions from fuel production, and more than 95% of toxic DPM emissions.
   
3. Innovative Clean Transit regulation. In December 2018, as part of its efforts to regulate mobile sources, CARB adopted the Innovative Clean Transit (ICT) regulation. Unlike numerous other CARB regulations, the ICT is not currently being challenged by the federal government. ICT is a statewide rule that requires public transit agencies to transition their bus fleets to zero-emission vehicles. Specifically, the ICT sets up two different timelines for large and small transit agencies. A large transit agency is defined as (1) any transit agency in the South Coast or San Joaquin Valley Air Basin that operates more than 65 buses in annual maximum service, or (2) any transit agency outside of these areas, but in an urbanized area with a population of at least 200,000 that operates at least 100 buses in annual maximum service. A small transit agency is any agency that does not meet either of these definitions.
   
   Under the ICT, large transit agencies are required to have 25% of their bus purchases in each calendar year be zero-emission starting on January 1, 2023, 50% be zero-emission starting on January 1, 2026, and 100% be zero-emission starting on January 1, 2029. Small transit agencies are required to have 25% of their bus purchases in each calendar year be zero-emission starting on January 1, 2026, and 100% be zero-emission starting on January 1, 2029. All transit agencies are required to fully transition all of their buses to zero-emission by 2040.
   
4. Heavy buses damage roads. As vehicles drive over roads, they exert pressure, causing wear, and thus damaging road surfaces over time. The amount of damage is proportional to the weight of the vehicle; however, this relationship is not linear. Instead, broadly speaking, road wear is generally thought of as being proportional to a vehicle’s axel weight to the fourth power^[1]. This means that doubling the weight of a vehicle can increase damage to the road by 16 times. Large vehicles, like trucks or transit buses, can weigh up to 20 times more than an average passenger vehicle, causing substantially more road wear than a typical passenger vehicle.
   
   Thus, in order to mitigate these effects, large vehicles have maximum weight loads. Current California law limits buses to a single axle weight of 20,500 pounds. However, numerous exceptions have been made over time, including for transit buses and zero-emission buses. As of today, the maximum allowed single axle weight for a zero-emission transit bus is 22,000 pounds.
   
5. Zero-emission bus availability. Currently, many zero-emission bus options are available to transit agencies across California, including both battery electric and hydrogen fuel cell options. However, these buses are not one-to-one replacements for the traditional buses currently used by transit agencies in terms of cost or performance. As a result, transit agencies are struggling to comply with the latest phase of ICT rules.
   
   These issues were highlighted in CARB’s comprehensive review^[2] of the ICT regulation ahead of the Phase II transition in 2026. This review was carried out before the 2026 rules came into effect in order to assess the readiness of transit agencies to conform with the regulations. Overall, while the report found that the market was generally able to support the required transitions to zero‑emission buses, there were key exceptions. Namely, the report identified issues surrounding a lack of necessary infrastructure and associated high costs with infrastructure deployment, and a lack of longer-range bus models.
   
   These problems are confounded by additional requirements on transit agencies from the federal government requiring them to purchase American-made vehicles and prohibiting them from purchasing Chinese zero-emission buses, which are among the cheapest and most advanced on the market. Currently, only two manufacturers have zero-emission buses available for U.S. transit agencies, Gillig and New Flyer.
   
   As a result, transit agencies do not have access to zero-emission buses with the range necessary to comparably replace their current fleets. Generally speaking, transit buses need a range of up to 300 miles, with additional margin to account for weather conditions, terrain, running HVAC systems, and battery degradation overtime. Presently, however, zero-emission buses available to California transit operators have ranges maxing out at roughly 250 miles.
   
   In order to increase bus ranges, bus manufacturers need to add additional battery capacity which in turn increases the weight. Current models, with lower ranges, are already at the statutory axle weight maximum in California. Therefore, according to the author, some kind of exemption is needed to allow bus manufacturers to find ways to increase range without substantially increasing weight.
   
   Indeed, writing as the sponsor of AB 1944, the California Transit Association states, “In December 2018, CARB adopted the ICT regulation, which requires public transit agencies to convert their bus fleets to zero-emission technology by no later than 2040. The regulation functions by way of a tiered zero-emission bus (ZEB) purchase mandate, which requires that, beginning in 2023, transit agencies purchase a fixed percentage of ZEBs with each bus procurement…As ZEB deployment continues to increase (and short-range ZEBs are deployed on available shorter routes), transit agencies will be required to procure ZEBs with extended ranges to complete longer routes and more aggressive duty cycles. With today’s technology, extended range ZEBs require additional batteries, which result in additional weight that meet or, in some cases, exceed the axle weight limits in current law.”
   
   Beyond the weight issues, cost is also a concern. A recent audit of East Bay Transit Agencies performed by the California State Auditor,^[3] found that the average zero-emission bus costs roughly twice as much as the average diesel bus. Multiplying this cost across the various agencies’ fleet sizes, the audit found that the costs generally far exceed agency revenues and reserves. Exacerbating factors further, the Federal Transit Administration has stopped awarding grants for purchasing zero-emission buses. As a result, the audit found that transit agencies will face difficulty meeting the ICT requirement and recommended that the Legislature extend the ICT deadline.
   
6. Creating axle weight exemptions, again. AB 1944 seeks to ease some of these burdens on transit operators by allowing them to operate heavier buses while industry works to catch up and supply buses compliant with the ICT. Specifically, this bill extends the dates by which transit agencies must reduce the weights of their zero-emission buses, pushing out the ultimate deadline for meeting the 22,000 pound curb weight requirement to 2032.
   
   However, this is not the first time limits on transit bus weights have had to be pushed off. AB 1706 (Eng, Chapter 771, Statutes of 2012) allowed transit operators to operate buses over the previously established 20,500 pound axle weight limit, and to procure further overweight buses through 2015. As the new 2015 deadline approached, AB 1720 (Bloom, Chapter 263, Statutes of 2014) provided an additional two-year exemption. Finally, AB 1250 (Bloom, Chapter 484, Statutes of 2015) aimed to address the issue in the longer term by creating a decreasing weight schedule that allowed articulated buses and zero-emission buses to slowly come into compliance with an increased 22,000 pound limit over a seven year period. This final deadline for 22,000 pounds was reached in 2022.
   
   As discussed above, however, this 22,000 pound limit is too restrictive to meet current needs. Currently, zero-emission bus manufacturers are attempting to offset weight increases associated with increased battery range by finding weight reductions in other areas throughout the bus. Manufacturers are counting on innovations in bus design and battery technology to reduce weights in time to meet the new deadlines for axle weight requirements put forward by this bill. However, absent a specific technological or design innovation, it is unclear if they will be able to do so, and thus this problem may reoccur in the future.
   
7. Local jurisdictions are concerned about road damage. While transit operators tout the need of a weight limit exemption, local jurisdictions, particularly cities, have raised concerns about increased road damage. A recent assessment of the condition of local streets and roads in California found an overall decrease in average pavement condition. Road condition is graded on the Pavement Condition Index (PCI), a value from 0 to 100, where 0 is a failed road and 100 is a pristine road. As of 2026, the total statewide PCI for local streets and roads had decreased relative to 2020, and the average road now has a PCI of 65, meaning an “at-risk” road.
   
   Importantly, as roads deteriorate more, they become exponentially more expensive to repair, meaning relatively frequent resurfacing is cheaper than waiting to replace a pavement entirely once it has degraded too much. However, even these more modest repairs are out of reach for many jurisdictions, as in 2025 alone there was a $54.2 billion shortfall in needed funding for maintaining pavement. As a result, many local roads across the state are at risk of further degradation, requiring more expensive repairs, and widening the shortfall even further.
   
   For these reasons, local jurisdictions are concerned about allowing the operation of heavier transit buses. Writing in opposition, the League of California Cities states, “AB 1944 authorizes higher axle weight limits for transit vehicles, which, by well-established engineering principles, will accelerate pavement damage on city streets. At the same time, the state’s transportation funding system, heavily reliant on SB 1 (Beall, Chapter 5, Statutes of 2017), is projected by the Legislative Analyst’s Office to decline by billions of dollars over the coming decade as zero-emission vehicle adoption increases. Without a corresponding funding solution, this creates an unsustainable mismatch between infrastructure wear and available resources.”
   
   One potential solution floated by some local jurisdictions is to allow transit operators to utilize lower weight, low NOx buses while waiting for advancements in zero-emission bus technology. While this would address the bus weight issue, it would violate and effectively nullify the ICT requirements by allowing the operation of GHG emitting buses. Ultimately, the Legislature should consider whether it wants to maintain the status quo, minimize road damage at the cost of increased transit emissions, or accept heavier buses and thus increased road wear in exchange for zero-emission transit buses.

Related/PREVIOUS Legislation:

AB 1250 (Bloom, Chapter 484, Statutes of 2015) – Exempted transit buses procured through a solicitation process before January 1, 2016, from the statutory weight limit of 20,500 pounds on any one axle and established a declining curb weight per axle.

AB 1720 (Bloom, Chapter 263, Statutes of 2014) – Provided a two-year exemption for existing transit buses to exceed statutory weight limits and sunset at the end of 2016. Additionally provided a weight exemption for transit buses if incorporating a new fleet class expansion.

AB 1706 (Eng, Chapter 771, Statutes of 2012) – Permanently allowed the operation of overweight transit buses on non-interstate highways that were procured before January 1, 2013. Additionally, it authorized transit operators to purchase new overweight transit buses to replace existing buses of equal or lesser weight, or to incorporate a new fleet class under specified conditions, until 2015.

FISCAL EFFECT: Appropriation: Fiscal Com.: Local:

POSITIONS: (Communicated to the committee before noon on Wednesday,

June 3, 2026.)

SUPPORT:

California Transit Association (Sponsor)

Alameda-Contra Costa Transit District (AC Transit)

California Electric Transportation Coalition

Monterey-Salinas Transit (MST)

Orange County Transportation Authority

Sacramento Regional Transit District

San Diego Metropolitan Transit System

San Mateo County Transit District (SAMTRANS)

Santa Cruz Metropolitan Transit District

Sunline Transit Agency

Transportation Agency for Monterey County (TAMC)

OPPOSITION:

League of California Cities

-- END --

1. Kinder, D & Lay, M 1988, Review of the fourth power law, Australian Road Research Board ARRB, Vermont South, Victoria, Australia. ↑

2. https://ww2.arb.ca.gov/our-work/programs/innovative-clean-transit/program-update ↑

3. https://www.auditor.ca.gov/reports/2025-120/ ↑

ASSEMBLY THIRD READING

ATR Bill Id:AB 1944

Author:(Lee)

As Introduced Ver:February 13, 2026

Majority vote

SUMMARY

Establishes higher weight limits up to 25,000 pounds on any one axle for zero-emission (ZE) transit buses.

Major Provisions

1. Establishes a maximum curb weight of 25,000 pounds on any one axle of a ZE transit bus procured through a solicitation process where the solicitation was issued between January 1, 2027 and December 31, 2027, inclusive.
2. Establishes a maximum curb weight of 24,000 pounds on any one axle of a ZE transit bus procured through a solicitation process where the solicitation was issued between January 1, 2028 and December 31, 2029, inclusive.
3. Establishes a maximum curb weight of 23,000 pounds on any one axle of a ZE transit bus procured through a solicitation process where the solicitation was issued between January 1, 2030 and December 31, 2031, inclusive.
4. Establishes a maximum curb weight of 22,000 pounds on any one axle of a ZE transit bus procured through a solicitation process where the solicitation was issued on or after January 1, 2032.

COMMENTS

Greenhouse gas emissions goals. The Legislature has set several goals to reduce greenhouse gas (GHG) emissions and address climate change. The Global Warming Solutions Act of 2006, AB 32 (Nuñez), Chapter 488, Statutes of 2006 and subsequent companion legislation SB 32 (Pavley), Chapter 249, Statutes of 2016, requires California to reduce statewide GHG emissions to 40% below the 1990 level by 2030. AB 1279 (Muratsuchi), Chapter 337, Statutes of 2022 establishes the policy of the state to achieve carbon neutrality as soon as possible, but no later than 2045. CARB is responsible for developing a Scoping Plan to detail how the state will achieve its GHG emissions reduction targets mandated by law.

Why regulate mobile source emissions? Mobile sources of air pollution are vehicles or equipment that can be moved from place to place and emit pollutants as they operate. These sources include on-road vehicles like cars, trucks, and buses, as well as non-road vehicles such as aircraft, construction equipment, and marine vessels. Mobile sources and the fossil fuels that power them are the largest contributors to the formation of ozone, GHG emissions, fine particulate matter (PM_2.5), and toxic diesel particulate matter (DPM). Statewide, more than 21 million out of over 39 million Californians live in areas that exceed the federal ozone standards; within these areas, there are many low-income and disadvantaged communities that are exposed to not only ozone, but also particulate and toxic, pollutant levels significantly higher than the federal standards which have immediate and detrimental health effects.

In California, mobile sources are responsible for approximately 80% of smog-forming nitrogen oxide (NO_x) emissions. They also represent about 50% of GHG emissions when including emissions from fuel production, and more than 95% of toxic DPM emissions.

The National Ambient Air Quality Standard (NAAQS). The Clean Air Act of 1970 instructs the U.S. Environmental Protection Agency (US EPA) to set primary NAAQS to protect public health, and secondary NAAQS to protect plants, forests, crops and materials from damage due to exposure to six criteria air pollutants. These pollutants include: particulate matter, ozone, nitrogen oxides, sulfur oxides, carbon monoxide, and lead.

Federal law (42 United States Code 7409 and 7410) requires that all states attain the NAAQS and develop State Implementation Plans (SIP) for nonattainment areas to attain the NAAQS, and attainment areas to maintain attainment. Failure of a state to reach attainment of the NAAQS by the target date can trigger penalties, including withholding of federal highway funds.

State law (HSC 39602) requires CARB to develop SIP emission reduction strategies for cars, trucks, and other mobile sources to meet the requirements in the Clean Air Act. Local air districts are primarily responsible for controlling emissions from stationary sources such as factories and power plants. CARB coordinates closely with local air districts (such as SCAQMD) in the development of attainment plans which are then incorporated into the SIP.

The state of California′s authority. Under the Clean Air Act, California has unique authority to set stricter than federal regulations for mobile source emissions after receiving a waiver from the US EPA. In January 2025, the Biden administration granted waivers to CARB for Advanced Clean Cars II (ACCII), Heavy-Duty Omnibus Low NO_x (Heavy-Duty Omnibus), Small Off-Road Engines, and In-Use Off-Road Diesel Fueled Fleets regulations. Additionally, partial waivers were granted for Commercial Harbor Craft, and Transportation Refrigeration Unit regulations. CARB also strategically withdrew waiver requests for Advanced Clean Fleets and In-Use Locomotive regulations prior to the Trump administration assuming office. In April 2025, three joint resolutions (H.J. Res.87, H.J.Res.88, H.J.Res.89) were introduced in the house to disapprove of numerous previously approved waivers, under the Congressional Review Act. On June 12, 2025, all three joint resolutions were signed into law. California immediately filed a lawsuit against the federal government to challenge the waiver revocations (State of California, et al. v. United States, et al. (United States District Court, Northern District of California, Case No. 4:25-cv-04966)). The lawsuit is ongoing, creating a state of uncertainty around many of California′s clean vehicle regulations.

Innovative Clean Transit regulation. CARB adopted the Innovative Clean Transit (ICT) regulation in December 2018. The regulation remains in force and is not currently challenged by the federal administration. The regulation is a statewide rule that requires public transit agencies to transition their bus fleets to zero-emissions (ZE). The ICT defines a large transit agency as a transit agency that operates in the South Coast or the San Joaquin Valley Air Basin and operates more than 65 buses in annual maximum service or a transit agency that does not operate in South Coast or San Joaquin Valley Air Basin and has at least 100 buses in annual maximum service in an urbanized area with a population of at least 200,000. All other transit agencies are defined as a small transit agency. Under the ICT, large transit agencies are required to have 25% of their bus purchases in each calendar year to be ZE starting January 1, 2023, 50% ZE starting January 1, 2026, and 100% ZE starting January 1, 2029. Small transit agencies are required to have 25% of their bus purchases in each calendar year to be ZE starting January 1, 2026, and 100% ZE starting January 1, 2029. All transit agencies are required to fully transition all of their buses to ZE by 2040.

ZE bus weights. The Larson Transportation Institute′s Bus Research and Testing Center, located in Altoona, Pennsylvania, was established in 1989 with funding provided by the Federal Transit Administration to perform heavy vehicle maintenance, repair and testing. The facility manages program operations associated with testing new model buses as required by federal law. Currently, the Center tests buses for maintainability, reliability, safety, performance, structural integrity and durability, fuel/energy economy, noise, and emissions. In accordance with the 1991 Intermodal Surface Transportation Efficiency Act, the Center tests brake performance, bus emissions, and buses using alternative fuels. Permanent facilities for testing and repairing vehicles that use hydrogen, gasoline, diesel fuel, compressed natural gas, liquefied natural gas, methanol/ethanol, propane, and battery-powered electricity have been in place since 1997.

The Center has released testing reports for 41 battery-electric (BE) buses and 4 hydrogen fuel cell (FC) buses. The curb weight on a single axel of tested BE buses ranges from 3,150 lbs. to 23,820 lbs. This bill would authorize all BE tested buses acquired through a solicitation process through December 31, 2029. The curb weight on a single axel of tested FC buses ranges from 5,510 lbs. to 21,550 lbs. This bill would authorize all FC tested buses acquired through a solicitation process in perpetuity. The weight of ZE buses is expected to decrease over time as technology matures and lighter materials are used in the manufacturing process.

Road wear and tear. Heavier vehicles wear roads more quickly than lighter vehicles. Additionally, the distribution of weight between vehicle axels is an added factor in road wear. The relationship between vehicle weight and road wear is calculated where road wear is proportional to the axel weight to the fourth power (Damage ∝ (Axle Load)⁴). Caltrans utilizes this relationship when designing roads.

Committee comments. California has ambitious climate goals and the state′s tools to reduce emissions from mobile sources are under attack from the federal administration. One of the remaining regulations California maintains is the authority to enforce is the Innovative Clean Transit regulation. However, transit agencies are restricted by state law which requires transit buses not to exceed specified curb weights. While previous efforts created short term solutions in hopes that battery weights would decrease over time, ZE transit bus weights have not decreased at the expected pace. This bill would provide relief for transit agencies to acquire any ZE bus through a solicitation that has been tested by The Larson Transportation Institute′s Bus Research and Testing Center, until at least December 31, 2029. As discussed, increased vehicle weights lead to increased road wear. This Committee should consider the tradeoffs between providing flexibility to transit agencies in their ZE bus acquisitions and the increased wear on California′s roads which would increase pressure on the amount of funding local agencies have for road maintenance.

According to the Author

″California has set ambitious zero-emission goals, requiring that by 2029 all buses purchased by transit agencies must be zero-emission vehicles. However, because of axle-weight limits set by the Legislature, transit agencies are struggling to procure Zero Emission Busses that keep up with their operational needs while staying within existing weight limits. AB 1944 provides a practical and responsible solution by adjusting the timeline for these limits while maintaining the previously negotiated upper weight cap, allowing California Transit Agencies to continue making progress towards our clean transportation goals.″

Arguments in Support

According to the California Transit Association, supporters of this bill, ″In December 2018, CARB adopted the ICT regulation, which requires public transit agencies to convert their bus fleets to zero-emission technology by no later than 2040. The regulation functions by way of a tiered zero-emission bus (ZEB) purchase mandate, which requires that, beginning in 2023, transit agencies purchase a fixed percentage of ZEBs with each bus procurement. Under the regulation, this fixed percentage increases every three years until, in 2029, it reaches 100 percent. In compliance with the regulation, transit agencies have already purchased 1,690 ZEBs (based on CARB′s 2024 estimates) and are preparing to procure ZEBs in increasingly larger volumes. As ZEB deployment continues to increase (and short-range ZEBs are deployed on available shorter routes), transit agencies will be required to procure ZEBs with extended ranges to complete longer routes and more aggressive duty cycles. With today′s technology, extended range ZEBs require additional batteries, which result in additional weight that meet or, in some cases, exceed the axle weight limits in current law.

″This bill aims to address this conflict between the state′s ICT regulation (and its mandate that transit agencies purchase ZEBs) and the axle weight limits that apply to ZEBs purchased by these agencies by postponing the solicitation issuance dates by which certain axle weight limits apply and without changing the maximum axle weight limit in current law.″

Arguments in Opposition

No opposition on file.

FISCAL COMMENTS

This bill is keyed non-fiscal by Legislative Counsel.

VOTES

ASM TRANSPORTATION: 15-1-0

YES: Wilson, Davies, Aguiar-Curry, Ahrens, Carrillo, Harabedian, Hart, Hoover, Jackson, Lackey, Papan, Ransom, Rogers, Sharp-Collins, Ward

NO: Macedo

UPDATED

VERSION: February 13, 2026

CONSULTANT: Aaron Kurz / TRANS. / (916) 319-2093 FN: 0002323

Date of Hearing: March 23, 2026

ASSEMBLY COMMITTEE ON TRANSPORTATION

Lori D. Wilson, Chair

ABPCA Bill Id:AB 1944 (

Author:Lee) – As Introduced Ver:February 13, 2026

SUBJECT: Zero-emission transit buses: axle weight

SUMMARY: Establishes higher weight limits up to 25,000 pounds for zero-emission (ZE) transit buses. Specifically, this bill:

1. Establishes a maximum curb weight of 25,000 pounds on any one axle of a ZE transit bus procured through a solicitation process where the solicitation was issued between January 1, 2027 and December 31, 2027, inclusive.
2. Establishes a maximum curb weight of 24,000 pounds on any one axle of a ZE transit bus procured through a solicitation process where the solicitation was issued between January 1, 2028 and December 31, 2029, inclusive.
3. Establishes a maximum curb weight of 23,000 pounds on any one axle of a ZE transit bus procured through a solicitation process where the solicitation was issued between January 1, 2030 and December 31, 2031, inclusive.
4. Establishes a maximum curb weight of 22,000 pounds on any one axle of a ZE transit bus procured through a solicitation process where the solicitation was issued on or after January 1, 2032.

EXISTING LAW:

1. Establishes a maximum gross weight of 20,500 pounds for any single axle of a bus. (Vehicle Code (VEH) 35554(a)(1))
2. Defines “curb weight” as the total weight of a fully loaded transit bus, including maximum fuel, oil, and coolant, and all equipment used in the normal operation of the bus, except without passengers or a driver. (VEH 35554(g))
3. Exempts transit buses from the above weight limit that were procured through a solicitation process that was issued before January 1, 2016. (VEH 35554(a)(2))
4. Exempts transit buses purchased by a publicly owned or operated transit system, or an operator of a transit system under contract with a publicly owned or operated transit system, from the above weight limit that were purchased during an option period in a multiyear contract before January 1, 2016, provided the option period does not exceed five years from the date of the original contract, or extend beyond January 1, 2021, whichever is earlier. (VEH 35554(a)(2))
5. Establishes a maximum curb weight of 23,000 pounds on any one axle of a transit bus procured through a solicitation process where the solicitation was issued between January 1, 2016 and December 31, 2018, inclusive. (VEH 35554(c)(1))
6. Establishes a maximum curb weight of 22,000 pounds on any one axle of a bus procured through a solicitation process where the solicitation was issued on or after January 1, 2019. (VEH 35554(c)(2))
7. Establishes a maximum curb weight of 25,000 pounds on any one axle of an articulated or ZE transit bus procured through a solicitation process where the solicitation was issued between January 1, 2016 and December 31, 2017, inclusive. (VEH 35554(d)(1))
8. Establishes a maximum curb weight of 24,000 pounds on any one axle of an articulated or ZE transit bus procured through a solicitation process where the solicitation was issued between January 1, 2018 and December 31, 2019, inclusive. (VEH 35554(d)(2))
9. Establishes a maximum curb weight of 23,000 pounds on any one axle of an articulated or ZE transit bus procured through a solicitation process where the solicitation was issued between January 1, 2020 and December 31, 2021, inclusive. (VEH 35554(d)(3))
10. Establishes a maximum curb weight of 22,000 pounds on any one axle of an articulated or ZE transit bus procured through a solicitation process where the solicitation was issued on or after January 1, 2022. (VEH 35554(d)(4))
11. Requires a transit operator operating an articulated transit bus to provide notice to all cities and counties in whose jurisdiction the bus will operate in the upcoming calendar year, identifying the approximate routes upon which the bus is expected to be scheduled for service, including the names of streets and roads upon which that service is likely to take place by July 1, 2016. Thereafter, a transit operator operating an articulated transit bus shall annually provide notice by July 1, to all cities and counties in whose jurisdiction the bus will operate in the upcoming calendar year, identifying any changes to the service on those routes and any new routes upon which the bus is expected to be scheduled for the upcoming year. The notice shall include data from information provided by the bus manufacturer to the transit operator, identifying the weight of the articulated bus. (VEH 35554(f))

FISCAL EFFECT: Unknown

COMMENTS: Greenhouse gas emissions goals. The Legislature has set several goals to reduce greenhouse gas (GHG) emissions and address climate change. The Global Warming Solutions Act of 2006, AB 32 (Nuñez), Chapter 488, Statutes of 2006 and subsequent companion legislation SB 32 (Pavley), Chapter 249, Statutes of 2016, requires California to reduce statewide GHG emissions to 40% below the 1990 level by 2030. AB 1279 (Muratsuchi), Chapter 337, Statutes of 2022 establishes the policy of the state to achieve carbon neutrality as soon as possible, but no later than 2045. CARB is responsible for developing a Scoping Plan to detail how the state will achieve its GHG emissions reduction targets mandated by law.

Why regulate mobile source emissions? Mobile sources of air pollution are vehicles or equipment that can be moved from place to place and emit pollutants as they operate. These sources include on-road vehicles like cars, trucks, and buses, as well as non-road vehicles such as aircraft, construction equipment, and marine vessels. Mobile sources and the fossil fuels that power them are the largest contributors to the formation of ozone, GHG emissions, fine particulate matter (PM_2.5), and toxic diesel particulate matter (DPM). Statewide, more than 21 million out of over 39 million Californians live in areas that exceed the federal ozone standards; within these areas, there are many low-income and disadvantaged communities that are exposed to not only ozone, but also particulate and toxic, pollutant levels significantly higher than the federal standards which have immediate and detrimental health effects.

In California, mobile sources are responsible for approximately 80% of smog-forming nitrogen oxide (NO_x) emissions. They also represent about 50% of GHG emissions when including emissions from fuel production, and more than 95% of toxic DPM emissions.

The National Ambient Air Quality Standard (NAAQS). The Clean Air Act of 1970 instructs the U.S. Environmental Protection Agency (US EPA) to set primary NAAQS to protect public health, and secondary NAAQS to protect plants, forests, crops and materials from damage due to exposure to six criteria air pollutants. These pollutants include: particulate matter, ozone, nitrogen oxides, sulfur oxides, carbon monoxide, and lead.

Federal law (42 United States Code 7409 and 7410) requires that all states attain the NAAQS and develop State Implementation Plans (SIP) for nonattainment areas to attain the NAAQS, and attainment areas to maintain attainment. Failure of a state to reach attainment of the NAAQS by the target date can trigger penalties, including withholding of federal highway funds.

State law (HSC 39602) requires CARB to develop SIP emission reduction strategies for cars, trucks, and other mobile sources to meet the requirements in the Clean Air Act. Local air districts are primarily responsible for controlling emissions from stationary sources such as factories and power plants. CARB coordinates closely with local air districts (such as SCAQMD) in the development of attainment plans which are then incorporated into the SIP.

The state of California’s authority. Under the Clean Air Act, California has unique authority to set stricter than federal regulations for mobile source emissions after receiving a waiver from the US EPA. In January 2025, the Biden administration granted waivers to CARB for Advanced Clean Cars II (ACCII), Heavy-Duty Omnibus Low NO_x (Heavy-Duty Omnibus), Small Off-Road Engines, and In-Use Off-Road Diesel Fueled Fleets regulations. Additionally, partial waivers were granted for Commercial Harbor Craft, and Transportation Refrigeration Unit regulations. CARB also strategically withdrew waiver requests for Advanced Clean Fleets and In-Use Locomotive regulations prior to the Trump administration assuming office. In April 2025, three joint resolutions (H.J. Res.87, H.J.Res.88, H.J.Res.89) were introduced in the house to disapprove of numerous previously approved waivers, under the Congressional Review Act. On June 12, 2025, all three joint resolutions were signed into law. California immediately filed a lawsuit against the federal government to challenge the waiver revocations (State of California, et al. v. United States, et al. (United States District Court, Northern District of California, Case No. 4:25-cv-04966)). The lawsuit is ongoing, creating a state of uncertainty around many of California’s clean vehicle regulations.

Innovative Clean Transit regulation. CARB adopted the Innovative Clean Transit (ICT) regulation in December 2018. The regulation remains in force and is not currently challenged by the federal administration. The regulation is a statewide rule that requires public transit agencies to transition their bus fleets to zero-emissions (ZE). The ICT defines a large transit agency as a transit agency that operates in the South Coast or the San Joaquin Valley Air Basin and operates more than 65 buses in annual maximum service or a transit agency that does not operate in South Coast or San Joaquin Valley Air Basin and has at least 100 buses in annual maximum service in an urbanized area with a population of at least 200,000. All other transit agencies are defined as a small transit agency. Under the ICT, large transit agencies are required to have 25% of their bus purchases in each calendar year to be ZE starting January 1, 2023, 50% ZE starting January 1, 2026, and 100% ZE starting January 1, 2029. Small transit agencies are required to have 25% of their bus purchases in each calendar year to be ZE starting January 1, 2026, and 100% ZE starting January 1, 2029. All transit agencies are required to fully transition all of their buses to ZE by 2040.

ZE bus weights. The Larson Transportation Institute's Bus Research and Testing Center, located in Altoona, Pennsylvania, was established in 1989 with funding provided by the Federal Transit Administration to perform heavy vehicle maintenance, repair and testing. The facility manages program operations associated with testing new model buses as required by federal law. Currently, the Center tests buses for maintainability, reliability, safety, performance, structural integrity and durability, fuel/energy economy, noise, and emissions. In accordance with the 1991 Intermodal Surface Transportation Efficiency Act, the Center tests brake performance, bus emissions, and buses using alternative fuels. Permanent facilities for testing and repairing vehicles that use hydrogen, gasoline, diesel fuel, compressed natural gas, liquefied natural gas, methanol/ethanol, propane, and battery-powered electricity have been in place since 1997.

The Center has released testing reports for 41 battery-electric (BE) buses and 4 hydrogen fuel cell (FC) buses. The curb weight on a single axel of tested BE buses ranges from 3,150 lbs. to 23,820 lbs. This bill would authorize all BE tested buses acquired through a solicitation process through December 31, 2029. The curb weight on a single axel of tested FC buses ranges from 5,510 lbs. to 21,550 lbs. This bill would authorize all FC tested buses acquired through a solicitation process in perpetuity. The weight of ZE buses is expected to decrease over time as technology matures and lighter materials are used in the manufacturing process.

Road wear and tear. Heavier vehicles wear roads more quickly than lighter vehicles. Additionally, the distribution of weight between vehicle axels is an added factor in road wear. The relationship between vehicle weight and road wear is calculated where road wear is proportional to the axel weight to the fourth power (Damage ∝ (Axle Load)⁴). Caltrans utilizes this relationship when designing roads.

Committee comments. California has ambitious climate goals and the state’s tools to reduce emissions from mobile sources are under attack from the federal administration. One of the remaining regulations California maintains is the authority to enforce is the Innovative Clean Transit regulation. However, transit agencies are restricted by state law which requires transit buses not to exceed specified curb weights. While previous efforts created short term solutions in hopes that battery weights would decrease over time, ZE transit bus weights have not decreased at the expected pace. This bill would provide relief for transit agencies to acquire any ZE bus through a solicitation that has been tested by The Larson Transportation Institute’s Bus Research and Testing Center, until at least December 31, 2029. As discussed, increased vehicle weights lead to increased road wear. This Committee should consider the tradeoffs between providing flexibility to transit agencies in their ZE bus acquisitions and the increased wear on California’s roads which would increase pressure on the amount of funding local agencies have for road maintenance.

According to the author, “California has set ambitious zero-emission goals, requiring that by 2029 all buses purchased by transit agencies must be zero-emission vehicles. However, because of axle-weight limits set by the Legislature, transit agencies are struggling to procure Zero Emission Busses that keep up with their operational needs while staying within existing weight limits. AB 1944 provides a practical and responsible solution by adjusting the timeline for these limits while maintaining the previously negotiated upper weight cap, allowing California Transit Agencies to continue making progress towards our clean transportation goals.”

According to the California Transit Association, supporters of this bill, “In December 2018, CARB adopted the ICT regulation, which requires public transit agencies to convert their bus fleets to zero-emission technology by no later than 2040. The regulation functions by way of a tiered zero-emission bus (ZEB) purchase mandate, which requires that, beginning in 2023, transit agencies purchase a fixed percentage of ZEBs with each bus procurement. Under the regulation, this fixed percentage increases every three years until, in 2029, it reaches 100 percent. In compliance with the regulation, transit agencies have already purchased 1,690 ZEBs (based on CARB’s 2024 estimates) and are preparing to procure ZEBs in increasingly larger volumes. As ZEB deployment continues to increase (and short-range ZEBs are deployed on available shorter routes), transit agencies will be required to procure ZEBs with extended ranges to complete longer routes and more aggressive duty cycles. With today’s technology, extended range ZEBs require additional batteries, which result in additional weight that meet or, in some cases, exceed the axle weight limits in current law.

“This bill aims to address this conflict between the state’s ICT regulation (and its mandate that transit agencies purchase ZEBs) and the axle weight limits that apply to ZEBs purchased by these agencies by postponing the solicitation issuance dates by which certain axle weight limits apply and without changing the maximum axle weight limit in current law.”

Previous and related legislation. AB 1250 (Bloom), Chapter 484, Statutes of 2015, exempted transit buses procured through a solicitation process before January 1, 2016 from the statutory weight limit of 20,500 pounds on any one axle and establishes a declining curb weight per axle.

AB 1720 (Bloom) Chapter 263, Statutes of 2014, provided a two-year exemption for existing transit buses to exceed statutory weight limits and sunset at the end of 2016. Additionally provided a weight exemption for transit buses if incorporating a new fleet class expansion.

AB 1706 (Eng) Chapter 771, Statutes of 2012, permanently allowed the operation of overweight transit buses on non-interstate highways that were procured before January 1, 2013. Additionally, it authorized transit operators to purchase new overweight transit buses to replace existing buses of equal or lesser weight, or to incorporate a new fleet class under specified conditions, until 2015.

REGISTERED SUPPORT / OPPOSITION:

Support

California Transit Association (sponsor)

Monterey-Salinas Transit District

Sacramento Regional Transit Center

San Diego Metropolitan Transit System

Opposition

None on file

Analysis Prepared by: Aaron Kurz / TRANS. / (916) 319-2093