Although traffic jams are probably here to stay, there seem to be very little art or design that address the problem in a creative way (in my work with Fiat some years ago, I worked with the highway as a playground and opportunity to generate social wireless interactions but it was purely speculative and did not materialize).
One of the few exceptions - and a concept that actually materialized - is FILEkit, a service briefly provided by a Dutch based group of architects called Artgineering
FILEkit (file is Dutch for traffic jam) is quite simply a collection of items such as a water pistol, a bible, a condom etcetera, which was distributed free of charge by a team of 'FILEangels' on motorcycles. The idea behind the interventionistic service was to turn a negative situation into a positive one by offering jammed motorists an excuse to step out and socialize with each other.
FILEkit was distributed in conjunction with the International Architecture Biennale in Rotterdam 2003. The kit is longer in production but at some point it could also be purchased in selected shops.