On-Road Heavy-Duty Certification Program
For decades the On-Road Heavy-Duty Certification Program has successfully implemented increasingly strict emission standards that have dramatically decreased particulate and nitrogen oxides emissions more than 90%. During this time, engines and vehicles have transformed from simple designs to complex systems with particulate filters and selective catalytic reduction, and will continue to evolve with hybrid, electric, and unforeseen technologies. The expertise of program staff enables evaluation of certification applications to keep pace with these technical developments in faithfully protecting the quality of air in California.