California's Heavy-Duty Low NOx Omnibus Regulation

California’s Air Resource Board (CARB) has passed what could be perhaps it’s last major regulation for reducing NOx and particulates from heavy-duty trucks and buses. The HD Low NOx “Omnibus” regulation practically touches upon every aspect of in-use emission reduction. Highlights summarized here –

Key Changes

By 2027, a 90% reduction of tailpipe NOx limit (vs 2010), resulting in a 20 mg/bhp-h standard over the HD FTP cycle
A 50% reduction in particulate mass (PM) limit by 2024.
A change in the procedure for analyzing real-world emissions, from the so-called NTE (Not-to-Exceed) to the European-style Moving Average Window (MAW) method. This will result in a greatly expanded coverage of the engine map over which emissions will be regulated.
Increased useful life for all vehicle classes. For Class 8 long-haul trucks, this increases from 435,000 mi to 800,000 mi by 2031. (Pause here for a second to think about it – emissions controls have to last 800K miles !)
On-board emissions NOx sensors and the requirement for OBD data transmission to regulatory authorities (telematics, already underway in China).

California's Heavy-Duty Low NOx Omnibus Regulation

Further Reading

Also see : California’s latest regulatory thinking for light-duty vehicles