Update Editor’s note: NVR 3/16/17: Napa officials talk about scrapping Hwy 29 widening in American Canyon
This is one of the few government acknowledgements that road widening doesn’t relieve traffic congestion, it enables future development and induces traffic increases to fill the lanes available, a fact already known to traffic researchers. This comes one day after the City of American Canyon presented their plans to widen Hwy 29 to encourage more development. The NVTA director then took issue with the reporting on this article in an editorial here. Kudos to the NVTA.
Dignitaries always flock to ribbon-cutting photo ops, but established traffic findings throw a damper on the champagne.
Research at UC Davis — one of the best in the nation on traffic studies — has shown that the widening of traffic arteries does not alleviate traffic congestion. In fact, as Professor Susan Handy who was a contributor to that research explained during her last April’s presentation at the NV2050 Forum on the Tourism Economy, the widening of traffic arteries alleviates traffic congestion for between one and two years and then makes congestion even worse than it was before. Though Caltrans has not yet adopted that policy, it has posted it on its website. In the face of overwhelming evidence, it will surely follow in time.
That the widening of arteries alleviates traffic congestion is intuitive but the reason why it makes it worse is more complicated.
During the congestion easing phase, all traffic increasing projects which undergo CEQA review evaluate current traffic conditions and are given a green light on their traffic impacts which they might not have gotten had those improvements not taken place. In other words, more traffic-increasing projects are approved than would have been otherwise. This facilitates more traffic until the previous saturation point is reached. But the net effect is that more traffic is dumped on the side streets of communities and overall congestion gets worse. Not to mention increased parking requirements.
A great example of this pattern is the Highway 29/Trancas Street underpass. For those who remember traffic conditions before those improvements more than a decade ago, there was a bottleneck at that location but nowhere else further Upvalley. That ribbon cutting celebrated the easing of traffic congestion. But here we are today, the percentage of pass-through traffic remains at less than 10 percent, but additional development was facilitated by valid CEQA review and here we are with the intolerable conditions of today.
It is great that the eyesore utilities have been placed underground and that the easier left turns will facilitate better traffic flow for a while, but overall traffic will increase because of them. When the rest of the developed world is abandoning traffic lights in favor of roundabouts, St. Helena will get one more of those traffic-delaying relics to facilitate an unwise development project. Make no mistake; even more development will slip under the CEQA radar during the coveted window and the quality of life of local up-valley communities will suffer.
Sip the bubbly with caution!
Weekly Calistogan 10/4/16: Highway improvements will increase traffic