By Paul Sousa, Director of Regulatory and Environmental Affairs

Questions from WUD members have continued to come in around the California Air Resources Boards (ARB) diesel truck regulations since the article I wrote in the Update a couple of weeks ago. I have some additional answers from ARB staff and wanted to share what I have learned with you. There are many specific scenarios I cannot answer here, but I would be happy to talk with you about your truck, so give me a call if you have any questions. As I wrote in the last truck article, it is buyer beware when purchasing used diesel trucks.

In one example, someone was looking at purchasing an older diesel truck to place it in the Low Use Exemption. They went to check with the DMV about transferring the title, but the DMV said they could not process the change in ownership because of a hold by the ARB. The buyer knew the previous owner could not use the truck because it was out of compliance with ARB. I contacted ARB on this and was informed that when a truck gets flagged by ARB enforcement as being out of compliance, one of the penalties is that that specific truck must be scrapped or sold outside of California. It can never be registered by anyone in California again. Currently, most trucks with 2006 model year and older engines are not in compliance unless they are currently using an extension, like the Ag Extension. If you are considering purchasing a truck with a 2006 or older model year engine with plans to use the Low Use or NOx Exemptions, make sure the truck has a current exemption before purchasing it. Note that the model year of the truck and the model year of its engine can be different, and I refer here to the model year of the engine as that is how the rule is written.

After January of next year, trucks with 2009 and older model-year engines will also require an exemption to continue operating. Those include the Low Use or NOx Exempt options. You must report your truck to the ARB through their online reporting system to get these options.

Another issue has to do with the supply chain issues that we are experiencing. Some truck owners planning on purchasing new trucks to replace trucks going out of compliance next January find that new trucks have a long wait time for delivery. ARBs truck rule has a provision to allow you to continue to use your old truck while awaiting delivery of a new compliant truck. You must follow specific requirements to use this manufacturer delay extension. One requirement is that you must have a purchase contract in place by September 1; more details can be found here:

Also, as I mentioned in the last article, if you are purchasing a compliant truck (model year 2010 or newer engine) make sure that all the emissions control systems are operating correctly as a new smog check requirement for diesel trucks goes into effect next year. If you need help with this or have any questions about these regulations, please contact me at 2095562490 or

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