Each time a major building development is planned, a traffic study is carried out. The surrounding roads are redesigned to ensure we can still get around like we could before the project was built, and the costs are shouldered by the developer, not the state. Sounds great, right?

In fact, traffic studies, and the roads they end up creating, make our cities much worse for pedestrians, for anyone not using a car, and for anyone living nearby. They also end up costing the state money, and bring extra congestion to existing highways and city roads. Let’s see why.

When a new development is proposed, typically the developer must do a traffic studies, or traffic impact assessment. Because traffic engineers are engineers, they usually over-engineer, and this, combined with the data from the assumptions, leads to huge intersections designed never to choke up. As you can imagine, that’s great for cars passing through, but terrible for anyone else.

As the traffic blog Urban Kchoze puts it:

Huge intersections like these tend to result in high-speed travel during most periods of the day when it is not congested, creating noise pollution and having the potential for very dangerous crashes … Their surplus capacity may also induce more vehicle traffic than would have happened otherwise. Finally, their huge size makes them a barrier to non-motorized travel.

Instead of a relatively small, slow-flowing road that can be crossed, we end intersections with 130-foot crosswalks, discouraging pretty much anyone sane from trying it. This leads to a self-fulfilling prophecy–future traffic studies assume that all travel is car-based, resulting in more road systems that can only be navigated by car.

This method also leads to sprawl. Because developers have to pay for any redevelopment of the roads, they favor building in areas that need little change. Developing in urban centers costs a fortune when you have to re-route or widen roads, so they look to the edge of town, where the roads aren’t yet near capacity.

The irony is that development in central urban areas wouldn’t necessarily increase road traffic, because many of the visitors would arrive on foot, or using existing public transit. But by developing at the edges of the city, these developments increase car use, further marginalizing alternate transport methods.