Diesel engines in their most common form in the US are heavy polluters. A simple gander at a Houston City bus, or smell, is more than enough to show this. Diesel engine use is necessary for large weight/pulling commercial trucks/construction etc, but there do need to be better alternatives that truely address emissions as well as fuel efficiency at the passenger car level.

Diesel motors in their most commonly used form are a big part of the air pollution problem around the world.

Hybrid vehicles such as the Prius, Honda Fit, Civic and others just around the corner are much better for air quality and are excellent for fuel efficiency. Diesel passenger cars arent a big player in the US anyway thankfully. The more hybrid small cars out on the roads means the closer we get to moving away and certainly lessening dependence on middle eastern oil, a terrible achilles heel for our nation.