Traffic in Princeton is driven overwhelmingly by people from outside Princeton driving into town to go to work.

Everyone has a theory about why traffic in Princeton is getting worse and worse, but if you want to understand why traffic volumes have grown in Princeton, it helps to look at the statistics. A thorough analysis of car journeys in Princeton, based on data from the US Census and the American Community Survey 2007-2011 has revealed that approximately 50,000 car journeys take place every day to get the Princeton workforce to and from their places of employment.

Every weekday morning, 22,606 car journeys are taken by people who live outside Princeton, coming into town to go to work. People who actually live in Princeton make a far smaller contribution to traffic. Just 4,753 Princeton residents make car-dependent trips to places of work outside Princeton, with 1,636 Princeton residents using cars to get to job sites within the town.

All of these statistics can get complicated*, so we made an illustration (above) to show where all the cars are coming from. The building in the middle is Nassau Hall, representing central Princeton. Princeton is a place where people walk to work far more frequently than in surrounding municipalities, as shown by the happy people out walking around. However, there are lots of cars, with four times as many cars coming into town than going out of town.

If we want to get serious about reducing traffic in Princeton, we ought to ask why so many people are driving into Princeton every day. Is it because they don’t like living in Princeton? For various reasons, some people prefer living elsewhere. But the fact that houses in Princeton cost up to double what is seen in other local municipalities shows that there is a big demand for living in in Princeton.

The problem is that Princeton is just too expensive for most workers. We have not allowed enough homes to be built to accommodate the huge number of people working in Princeton. This means that Princeton’s workforce is drawn from other less-expensive communities in the region, and we have lots of traffic as people drive in and out to work. It’s not reasonable to blame commuters for living in other places and driving into Princeton. They are just following the logic of a housing market where Princeton is far more expensive than surrounding areas.

Adding more homes in Princeton is often opposed by local residents on the false assumption that it will cause traffic to increase. The data shows that the opposite is true. The major cause of traffic is the lack of places for people to live in Princeton, requiring them to make car journeys to get to work. We can reduce area traffic and pollution byletting more people live where they work, right here in Princeton.

* If you want more data, not less, then you can access a wealth of information gathered from the US Census, American Community Survery and elsewhere by clicking this link