Well I've been driving for a long time but today was a new experience. Passed what I thought was a truck inspection setup along side the beeline highway here in Arizona and a poorly written sign said all diesel trucks, pickups and cars to turn in. I was driving my trusty 240D and couldn't believe that they wanted diesel cars. So kept on going and got a nasty look from one of the DPS officers. I expected to see flashing lights in the mirror but was lucky. What are they looking for?

Oily
1981 240d
1987 300d turbo
1973 220