Enviro-fem,
From my reading of the regulation there do not appear to be any exclusions for the release from vehicles. However, I don't think the average vehicle could release a reportable quantity of hazardous substance.
Benzene has an RQ of 10 pounds. The concentration of benzene is somewhere around 700 ppm depending upon the blend. To release that 10 pounds to the environment you would have to spill more than 15000 pounds of fuel.
Just curious, is there over riding concern?
MikeCJ