Understanding California’s Clean Air Mandate

If you operate a fleet of work trucks or vans in California, you know that navigating the state’s air quality regulations is a critical part of doing business. As of 2025, these rules are becoming more stringent, and understanding them is essential to avoiding significant penalties and planning for the future of your fleet. The most significant regulation impacting businesses now is the Advanced Clean Fleets (ACF) rule from the California Air Resources Board (CARB).

This regulation can seem complex, but its goal is simple: to push commercial fleets toward zero-emission vehicles (ZEVs). For small business owners, this isn’t a distant future concern; it’s a reality that requires immediate attention and strategic planning. This guide will break down what you need to know in straightforward terms.

Does the Advanced Clean Fleets (ACF) Rule Apply to You?

The first step is to determine if your business falls under the ACF regulation. The rule primarily targets what CARB defines as “High Priority Fleets.” You are considered a High Priority Fleet if you meet any of these conditions:

• Your business had $50 million or more in gross annual revenue in the previous year.
• You own, operate, or control a total of 50 or more vehicles with a Gross Vehicle Weight Rating (GVWR) of over 8,500 lbs.
• You are a federal government agency.

If your business operates entirely under those thresholds, you may not be subject to the main compliance pathways of the ACF rule yet. However, it’s critical to understand that the direction of all state regulations is toward zero emissions, making this a crucial time to start planning.

Your Compliance Options: The Model Year Schedule vs. ZEV Milestones

For businesses that do qualify as a High Priority Fleet, CARB provides two main pathways for compliance.

The first, and simpler, option is the Model Year Schedule. This path dictates that starting January 1, 2025, when you add a new vehicle to your California fleet, it must be a ZEV if a ZEV option is available for that specific vehicle type. When it’s time to replace an existing internal combustion engine (ICE) truck, you must replace it with a ZEV if one is available. Essentially, you must remove the ICE vehicle from your California fleet (either by selling it, moving it out of state, or retiring it) by the end of its “useful life,” as defined by a set schedule from CARB. This approach forces a gradual, replacement-based transition to zero-emission vehicles.

The second, more flexible but complex option is the ZEV Milestones Option. This pathway allows a fleet owner to continue purchasing gasoline or diesel vehicles, but requires them to meet an increasing percentage of ZEVs in their overall fleet over time. For example, for a fleet of light-duty package delivery vans, 10% of the fleet must be ZEV by 2025, scaling up to 100% by 2035. This option provides more control over the timing of your ZEV purchases but requires diligent tracking and long-term strategic planning to ensure you meet the mandated milestones.

Navigating the Road Ahead

The transition to a zero-emission fleet is a significant undertaking, but it doesn’t have to be overwhelming. The most important action you can take today is to fully understand your obligations under the current CARB regulations. Determine if you are a High Priority Fleet and, if so, carefully evaluate which compliance pathway makes the most sense for your business operations and financial planning.

Even if you are not currently subject to the rule, the message from the state is clear. Begin researching electric vehicle options, investigate available state and federal incentives, and start planning your fleet’s long-term transition. Staying ahead of these regulations is the smartest way to ensure your business remains compliant, competitive, and successful in California for years to come.