If you received (and read) the most recent edition of Councilor Jake Auchincloss’s newsletter, you got a treat: an informative (and fun!) discussion of the economics of traffic. Go ahead and read it. We’ll wait.

As Jake explains, traffic is as much economics as engineering. Traffic follows the law of supply and demand. The key insight over the last several years is that demand for cheap car travel is effectively unlimited. If you add capacity (say add a lane to 128/95), you won’t simply spread out existing demand for three lanes over four lanes and improve traffic flow. People who were previously deterred from driving because of the low throughput will see the improved conditions and now drive. The additional capacity is almost immediately consumed by new drivers. And, you’re back to the previous state of congestion, just with more cars. This phenomenon is called “induced demand.” Congestion does not reflect all of the demand jockeying for the limited capacity. There is always latent demand. Always.

In his newsletter primer, Jake also explains that you can induce demand with additional parking, just as much as with adding travel lanes. Parking is a limit on the capacity of our motor-vehicle travel network. Even if you can drive to your destination on free-flowing roads, if you can’t park you’re car at the end of the trip, you are deterred from driving. Likewise, if you can’t get free or cheap parking where you live, you’re not going to be able to drive away from your home. Creating parking creates the ability to drive. Creating parking induces demand for our roadways. Parking helps cause congestion.

This has obvious consequence at Northland and other developments in the city and also in the proposed zoning reform. Land Use regulations manifest a concern that there be enough parking. Given what we know about parking and its impact on traffic, we should be concerned about too much parking.

Jake’s got it right on this one.

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