Thread by @nathanfletcher

At today's SANDAG Transportation Committee we had a discussion on individuals preference to widen freeways. I understand the desire to reduce congestion BUT it is important to note what has been learned and how widening freeways can actually INCREASE congestion. #InducedDemand

To get an understanding of the potential negative impacts of freeway expansions can do we can look at the I-10 “Katy Freeway” expansion in the Houston metro area. One of the widest freeways in the world. It was widened to a whopping 26 lanes at a cost of almost 3 billion dollars.

All of this was done with the goal that the freeway expansion would alleviate traffic congestion. After widened, congestion got worse. Houston’s traffic monitoring agency noticed a 30% increase and 55% during the evening commute between 2011 and 2014. It was an expensive failure.

The occurrence is based in the concept of “Induced Demand.” Essentially the wider and bigger a freeway gets the lower the “cost/time” is to use the road. As people think more space and lower congestion then more people drive and they drive more per person. citylab.com/transportation…

Simply, building more roads means people drive more. Professor Duranton @Wharton has documented this phenomenon starting, "As soon as you manage to create space on the road, by whatever means, people are going to use that space."
For more information: aeaweb.org/articles?id=10…

This concept is also a major takeaway from the epic biography of Robert Moses in "Power Broker"stating: "Watching Moses open the Triborough Bridge to ease congestion on the Queensborough Bridge, open the Bronx-Whitestone Bridge to ease congestion on the Triborough Bridge and...

then watching traffic counts on all three bridges mount until all three were as congested as one had been before, planners could hardly avoid the conclusion that "traffic generation" was no longer a theory but a proven fact: the more highways were built to alleviate congestion,

the more automobiles would pour into them and congest them and this force the building of more highways – which would generate more traffic and become congested in their turn in an ever-widening spiral that contained the most awesome implications for the future of New York."

It is time as a region that we embrace lowering congestion by providing more transportation options to help get people off the roads (transit, bike, walk). It is also essential we align our land use planning to put housing near jobs and near transit corridors.

This is the only way to successfully lower VMT, GHG and reduce congestion. We can NOT pave our way out of this problem. We CAN take lessons learned and build a regional transportation system for the next 100 years.