Basic economics of car traffic

Experts recommend loosening your belt to fight obesity.

Economics is the study of scarcity and choice, and that study can be applied to travel behavior. Induced demand is one example, related to the supply and demand of mobility options.

Way back in the 1950s, as new car lanes were built across America, they immediately filled up with cars. Seems obvious, right? Americans were buying automobiles so naturally they needed a place to operate them. Build a road and people will use it.

But as obvious as the induced demand concept is, government agencies from the Feds down through local townships are looking for ways to widen roads to ease congestion. More car lanes to remove car traffic. I hope you’re facepalming right now.

Infrastructure induced demand works like this:

• The 4-lane street between home and your favorite restaurant is packed with cars at 6 PM, so you take a different route or you wait until traffic clears up.

• But then the state builds a new lane in each direction to remove rush hour congestion. Now you’ve got all that empty space. You can hop on the newly widened 6-lane street and zip over to the restaurant at 6 PM. No need to wait for traffic to clear up!

• Soon everyone else in the area discovers the same thing, and the 6-lane street is all clogged up at 6 PM. 

• You go back to taking a different route or waiting until traffic clears up.

When you step back from the emotional arguments about fighting traffic, the whole process looks like a slapstick comedy. Animate it as a children’s cartoon, and they’d split their sides laughing at the silly grown-ups. 

When public agencies make transportation networks easy and appealing for car traffic, then just like that, the networks fill up with car traffic. It’s that simple. 

Every time there's a new infrastructure bill, highly educated and credentialed people clamor for federal funding to add more car lanes.

There are many ways for local and state agencies to use infrastructure funding for projects other than road widening. 

1. Maintain what’s already been built.

2. Expand capacity for walking.

3. Operate a vanpool or bus service.

4. Install protected bicycle networks. 

5. Narrow the car lanes.

6. Replace traffic signals with roundabouts.

7. MAINTAIN WHAT’S ALREADY BEEN BUILT.

The next time someone sounds the alarm about the need for more lanes to reduce car traffic, turn the conversation to induced demand. I don’t know exactly what your community needs, but I know more car lanes aren’t the remedy.