CSAC Bulletin Article

Counties Share Feedback on Advanced Clean Fleets Regulation

The Advanced Clean Fleet (ACF) regulations are part of a decades-long effort by the California Air Resources Board (CARB) to reduce greenhouse gas emissions. In support of Governor’s Executive Order N-79-20, the ACF regulations require all public fleet owners to begin replacing their medium and heavy-duty fleet vehicles with Zero-Emission Vehicles (ZEV). The most common types of compliant ZEV’s utilize either battery-electric components or hydrogen fuel cell technology. The ACF regulations offer two options for compliance:

  • Purchase Option: Beginning in 2024, fleet managers must ensure that 50% of their medium & heavy-Duty Vehicle (vehicles with a Gross Vehicle Weight Rating of 8,500 lbs. and above) purchases are ZEVs. This percentage escalates to 100% for all medium & heavy-duty vehicle purchases in 2027. Beginning January 2027, counties with 10 or fewer impacted vehicles as well as fleets in 25 low-population counties must ensure 100% of their vehicle purchases are ZEVs.[1]
  • Fleet Percentage Option: Elect to meet ZEV fleet composition targets using the ZEV Milestones Option, which requires fleets to ensure they have a certain percentage of ZEV medium and heavy-duty vehicles based on function by specific years. Details on this option are available.

The Institute for Local Government launched a survey in September 2023 to assess a variety of factors that will impact local government’s (cities, counties and special districts) ability to implement the regulations. CSAC is proud to report counties had the highest response rate, with 79% of counties responding to the survey. Additionally, 87% of county fleet managers were aware of the ACF regulations. This level of response and awareness provides a high confidence level and will greatly assist CSAC’s advocacy efforts on the ACF regulations going forward.

The following are the top survey results of interest to counties. The responses can be grouped into three main categories – Fleet Statistics, Fleet Duty Cycles, ACF Implementation and Future Needs.   

Fleet Statistics

Obtaining better data on the total size of county vehicle fleets is a key first step to setting the context for the impact that the ACF regulations. Most counties (82%) reported fleets of 100 or more vehicles with 60% of respondents having more than 251 total vehicles in their fleets. As expected, the number of medium and heavy-duty vehicles in county fleets had greater variability with 60% of respondent’s fleets having 100 or fewer of these vehicles. However, with 40% of respondents having 251 or more impacted vehicles, the combined demands of county fleets to purchase sufficient compliant vehicles are likely greater than the current limited capacity of manufacturers of medium and heavy-duty ZEV’s.

Fleet Duty Cycles

Counties maintain vehicle fleets to serve specific needs that assist them in delivering critical services to the public. Counties will assess the duty cycle required for the task to determine the best what vehicle is needed to support employee tasks. In simple terms, this can mean the hours per day the vehicle will work, the amount of power required for tools (i.e. winches, cranes, pumps, welding equipment, etc.) as well as hauling and towing capabilities. Duty cycles include considering if the vehicle can be left at a remote work location far from the fleet yard for days at a time. Fleet managers must assess the number and types of vehicles they need to meet duty cycle and work needs while also calculating a cushion to accommodate for required vehicle maintenance and unscheduled repairs.

County fleet managers’ survey responses expressed strong concerns on whether electric ZEVs will be able to meet the duty requirements of existing medium and heavy-duty vehicles. Fleet managers indicated that they would need to purchase 2-3 battery electric medium or heavy-duty vehicles to replace the duty cycle capabilities of one internal combustion engine. Additionally, other commenters noted that many of their vehicles don’t return to the county fleet yard each day as operations in remote areas of their county mean that the most efficient choice is to leave the vehicle at the work site overnight for several days. In these situations, county staff would need to transport a generator to recharge a battery-electric ZEV overnight to ensure it was able to function the next day.

Fleet managers noted there are many duty cycles, such as emergency road closures, critical infrastructure failure repairs and long-distance travel to repair sites in which there is simply no electric ZEV capable of performing the required tasks. This was reiterated by 86% of county respondents indicating the ACF regulations will be a challenge for their agency’s ability to reliably respond to and provide services in emergencies. This is critical as the regulations only allow exemptions for public safety (i.e. police, fire, ambulance) vehicles from the ZEV requirements. Table 1 illustrates the operations factors that county fleet managers are most concerned with ZEVs performing.

Table 1

Question: Does your agency have any of the following concerns about switching your fleet to ZEV?

Operations Factor*


Infrastructure needs




Limited use/range


Emergency preparedness & response concerns


Market availability of vehicle class


Electrical reliability concerns


Maintenance concerns




*Note: Respondents were allowed to select multiple options for these responses

ACF Implementation

Counties indicated implementation of the ACF regulations pose several challenges. Many respondents indicated that ZEV versions of the medium and heavy-duty vehicles they require are not currently being manufactured and that pricing was not readily available in the small number that could meet their needs. Like duty cycle concerns, respondents consistently indicated that it was unclear if current and proposed ZEV chassis could accommodate the needs of additional up-fittings, such as toolboxes, cranes, winches and other equipment that these public works vehicles require. Table 2 provides details on the issues Fleet Managers believe will hinder their ability to implement the ACF regulations.

Table 2

Question: Are any of the listed factors below a concern to your agency that may impact the successful implementation of the ACF regulation?

ACF Implementation Factor*


Infrastructure refueling/recharging capabilities


Lack of funding


Electrical utility delays


Market availability


Lack of staff capacity/expertise


Permitting process








*Note: Respondents were allowed to select multiple options for these responses

A common concern for ACF implementation is on challenges with acquiring the electrical infrastructure needed (i.e. Recharging capabilities & Electrical utility delays) to power medium and heavy-duty ZEVs, with funding and availability following closely behind. Nearly all counties face costs and timeline challenges working with their local electric utilities to acquire transformers and other equipment needed to improve electrical capacity of their local grid to support ZEV charging equipment[2]

The lack of staff capacity to service and repair ZEVs requires additional consideration. County fleets rely on trained service workers to maintain and repair their existing fleet of vehicles. Switching vehicle modes of power, specifically gas/diesel to electric or hydrogen, presents an entirely different set of technical skills. This will require counties to retrain many of existing technicians and hire ZEV trained technicians to ensure they are able to maintain these vehicles. There is already a shortage of EV trained automotive technicians worldwide, which will limit counties’ ability to hire these personnel[3]. This is further compounded by the difficulties that all levels of government, including counties, have had for filling existing positions across all departments[4].

Future Needs

Throughout the survey it became clear it would take years to meaningfully address the identified implementation issues raised within the survey. 97% of respondents indicated they were unlikely able to implement the ACF regulations by either the Purchase options 2024/2027 deadline or the Fleet percentage options 2025 deadline.

The clear and well-founded concerns articulated by county fleet managers support the conclusion that changes are needed to make the ACF regulations. The strong response that additional time and funding is needed for successful implementation aligns with the fleet managers’ concerns related to ZEV availability and costs as well as utility costs and delays. Table 4 provides a summary of the resources fleet managers indicated they needed from the state to assist with ACF implementation.

Table 4

Question: What support or resources are needed from the state to assist with the implementation of the ACF regulation?

Support Need*


Extended Implementation Deadline




Expanded Vehicle Exemptions


Inventory of Available Manufacturers


Technical Assistance


Supplier Pricing Caps


Educational Resources and toolkits




*Note: Respondents were allowed to select multiple options for these responses


The survey concludes CARB should enhance and expand the technical assistance and educational resources to counties and local governments to support this program.  Although supplier pricing caps are likely outside of CARB’s authority to impose, the Board should periodically review and update its implementation cost analyses to consider utility related costs as well as ZEV purchase and maintenance expenses.



[1] ARB has designated the following as low population counties: Alpine, Amador, Butte, Calaveras, Colusa, Del Norte, Glenn, Humboldt, Inyo, Lake, Lassen, Mariposa, Mendocino, Modoc, Mono, Nevada, Plumas, Shasta, Sierra, Siskiyou, Sutter, Tehama, Trinity, Tuolumne, and Yuba.

[2] https://www.cbsnews.com/sacramento/news/california-facing-eletrical-transformer-troubles-as-new-homes-continue-to-be-built/

[3] https://www.reuters.com/business/autos-transportation/ev-broken-finding-technician-fix-it-may-take-while-2023-09-06/

[4] https://www.governing.com/work/local-governments-search-for-answers-to-hiring-challenges

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