Some small pilot studies have been carried out in Europe, often with successful results. Basically, the idea is that we become more alert when a situation requires us to be. An intersection that appears riskier forces us to give it more conscious and subconscious attention.
http://knowledge.allianz.com/mobility/transportation_safety/...
Anecdotally, I can certainly testify to the effects of traffic lights on traffic. I grew up and worked for a lot of my life in LA, a city as famous for its traffic as for its movies and weather. There are certain parts of the city in which every damned block has a traffic light, and blocks are very short in the denser areas. These areas are traffic hellholes. Beverly Hills in rush hour would have made a cameo appearance in Dante's Inferno, had he been around to experience it.