Drivers and city engineers have long known that traffic jams can mysteriously appear without any obvious cause once the volume of cars on the road gets too large.

MIT mathematicians, inspired when a group of Japanese researchers demonstrated the formation of spontaneous traffic jams on a circular roadway with real drivers, have developed a mathematical model that explains how these jams form out of the slightest disturbance.

According to Aslan Kasimov, one of the researchers, the key insight was that the traffic jams follow mathematics resembling those of the detonation waves in explosions.

"We wanted to describe this using a mathematical model similar to that of fluid flow," said Kasimov.

The group found that, like detonation waves, these traffic jams have a point that separates the traffic flow into upstream and downstream components that have completely different traffic flow.
The researchers hope the model will help engineers design roads that minimize the chance of spontaneous jams occurring.

The Bureau of Labor Statistics says that mathematicians held about 3,000 jobs in 2006. However, many people with mathematical backgrounds work in other occupations, such as the 54,000 jobs as postsecondary mathematical science teachers that year.