A couple of the car-oriented sites I read regularly mentioned this story about a highway project that drew so much road rage from drivers that the California Department of Transportation decided to close the road to traffic completely for the duration of the project. One worker was hit by a thrown burrito, one was allegedly clipped by a driver, and one guy threatened to climb a tower and start shooting at the road workers.
First, you have to wonder what sort of brain-damaged subhumans would commit acts of violence against the very people working to improve the road they use. The closure of the road in question has added miles and minutes to drivers' commutes.
Second, how is it that something like this hasn't already happened here in the land of the Massholes?