We all know that road rage has been an issue of concern and study for many years. See, for instance, these two books in the Transportation Library's collection.
Garase, Maria L. Road rage. New York : LFB Scholarly Pub.,2006.
HE 5620.P9 G212
and
Walters, Carol H. and Scott A. Cooner Understanding road rage : evaluation of promising mitigation measures.
College Station, Tex. : Texas Transportation Institute, Texas A&M University System ; [Springfield, Va. : Available through the National Technical Information Service, 2001.
http://tti.tamu.edu/product/catalog/reports/4945-2.pdf
HE 5620.P9 U55 pt.2
The Onion presented a humorous but elegant solution several years ago that provides not only a channel for the anger, but a more fuel-efficient car as well!