I have prepared a terribly photoshopped (MS paint, actually) rendition:

This idea is great. Each artwork can be attached to a low-radius radio transmitter so that as you idle beside it, you can tune in to 88.1FM (say) and hear a pleasant description of the work's aesthetic significance and history.
In line with the automotive theme, each painting will be outfitted with a windshield wiper and cleaning-fluid jet for periodic washing away of exhaust buildup.