NOx Exempt Area Vehicles with GVWRs 14,001 to 26,000 lbs Based on Regulation Adopted on April 25, 2014

Lighter vehicles (GVWR 14,001 to 26,000 lbs) that operate entirely in NOx Exempt Areas are exempt from having to meet 2010 engine emission standards provided they meet PM BACT (diesel particulate filter).

At its April 25, 2014 board hearing ARB adopted major changes to the NOx Exempt Area provisions.

The NOx exempt areas were the following counties: Alpine, Colusa, Del Norte, Glenn, Humboldt, Lake, Lassen, Mendocino, Modoc, Monterey, Northern Sonoma, Plumas, San Benito, San Luis Obispo, Santa Barbara, Santa Cruz, Shasta, Sierra, Siskiyou, Trinity, Tehama, and Yuba.

The following counties or areas were added: Amador; Butte; Calaveras; Eastern Kern (portion of Kern County within the Eastern Kern Air Pollution Control District); Inyo; Mariposa; Mono; Nevada; Northern Sutter (portion of Sutter County that is north of the line that extends from the south east corner of Colusa County to the southwest corner of Yuba County); portions of El Dorado and Placer that are within the Lake Tahoe Air Basin, Tuolumne.

Previous text on this exemption was really confusing and revised text is still unclear. Our understanding is that light trucks can be exempt from having to meet 2010 engine standards provided they are retrofit by either of the two compliance schedules given below.

Compliance by Percentage of Total Fleet of Lighter Trucks

Date % Trucks Must
Have PM Filter
% of all lighter
trucks that must
have a PM filter
Jan 1, 2014
Jan 1, 2015, 25%
Jan 1, 2016 40%
Jan 1, 2017 55%
Jan 1, 2018 70%
Jan 1, 2019 85%
Jan 1, 2020 100%

Compliance by Engine Model Year

Date Truck Must
Have PM Filter
Engine Model Year
Jan 1, 2015 Pre 1996
Jan 1, 2016 1996
Jan 1, 2017 1997
Jan 1, 2018 1998
Jan 1, 2019 1999
Jan 1, 2020 2000-2003
Jan 1, 2021 2004-2006

Also note that any truck retrofit with a DPF before Jan 1, 2014 does not have to meet 2010 engine standards until Jan 1, 2023. Hence, if you have a truck you retrofit before Jan 1, 2014 you can use it anywhere you want until Jan 1 2023. By that date it must meet 2010 engine standards or be declared/labeled NOx area exempt.

Vehicles designated as NOx area exempt must be labeled when the exemption is used. The labeling requirement is as follows:

The letters NE shall be white block lettering on a black background. Both letters shall be at least three inches high on a five by eight inch background. The label shall be located on the left and right door of the vehicle and in clear view at all times.

ARB has an FAQ on this topic. Click on "NOx Exempt" at:
Truck and Bus Regulation Fact Sheets and Reporting Documents