Traffic routing

My dad did most of his PhD work on modeling traffic patterns and routing procedures that try to minimize delays. The link below goes to an abstract of one of his articles where he develops a model for traffic lights when there is a high-occupancy vehicle present (you can buy the full article for $31.50). Sensors and timers based on the time of day are commonly used to route traffic, but when a bus is carrying the equivalent number of people as 40 cars, there needs to be some sort of preferential treatment to the bus. But also you don't want to give the bus total preference over traffic signals like an ambulance or squad car. What my dad did was incorporate all the inputs available to create a socially optimal routing system.

http://en.scientificcommons.org/38284759

In this article, the author talks about some references involving the Big Dig, which is a large road network in Boston built to help traffic in throughout Boston.
http://www.weeklystandard.com/Content/Public/Articles/000/000/012/555ivsyw.asp

Traffic routing is not the most simple concept. The means are to create a way for cars to get from point A to point B faster, and limit congestion. However, that is not always the case, and unforeseen circumstances prevent road networks from working properly. One aspect that is not favorable of using an advanced highway system like the Big Dig is that it cost an extremely large amount of money to construct, and the maintenance required to oversee the roads is extensive. If the roads are seen as dangerous and costly, people may not want to use the highway and stick to the side roads, which will increase the cumulative delay on the overall traffic network.