Most new heavy duty diesel…

Most new heavy duty diesel engines now have a particulate sensor that notifies the operator if too much soo is getting passed the diesel particulate filter.
Also, most heavy duty diesel engines are required to notify the driver when the emissions are out of compliance. Depending on the fault the engine will gradually derate itself the longer the driver drives the truck while being out of compliance. I don't see the need to test the emissions on new heavy duty diesel engines because they're designed to test and police themselves. Checking for MIL or CEL being on at time of safety or checking OBD status should be enough.