As of 2006, SUVs were classified as “light trucks,” and thus allowed to exceed e

If one assumes that drivers have a responsibility to minimize their impact on others, then one might hold that emissions should be minimized. Some probably oppose government intervention for any number of reasons.

Voluntary emissions standards may or may not work. By now, individuals are probably at least minimally aware of the environmental impact of SUVS. Sales, however are increasing. One could therefore assume that lowering emissions are not a high priority among SUV buyers and that there is little incentive for the car makers to lower emissions.