Currently viewing the tag: "induced demand"

Traffic on 826

There are several reasons why widening highways is usually a futile strategy to combat traffic congestion. For one, highway widening projects are costly and time consuming. It has also been well documented that adding new capacity to highways creates induced demand, which essentially means it will generate more traffic on the road. Consequently, over time the widened highway gradually fills up with additional traffic until it reaches a threshold, and is congested again. Of course, just the principle of widening highways is flawed because it encourages driving, it’s unsustainable, and it raids funds for other major transportation projects that are much more sustainable, such as transit. However, research from the Sightline Institute points out that widening highways also leads to substantial increases in GHG emissions in the mid-to-long term.

Conventional dogma preached by road-widening enthusiasts claims that additional capacity will decrease GHG emissions by easing traffic congestion. According to Sightline, this limited benefit only holds true in the short term, if at all. In the medium-to-long term, however, adding one mile of new highway lane will result in an increase in CO2 emission by more then 100,000 tons over 50 years. To quantify that, at current rates of emissions, 100,000 tons of CO2 equals the 50-year climate footprint of about 100 typical U.S. residents.

Image: Sightline Institute

Apparently Turnpike planners have missed the boat on established best practice metropolitan transportation policy. According to the Herald, they will be discussing their preliminary ideas to decongest the Turnpike, including a plan to expand the expressway to 10 lanes between 836 and 874, and possibly all the way to Homestead. I guess they want to do everything in their power to justify sprawl and make South Florida as unsustainable as possible.

When are these people going to learn that a “predict and provide” approach to building highways is both counter-productive and unsustainable? It’s been addressed over and over and over again by researchers that widening highways such as the Turnpike, especially at its current capacity, does little but induce more driving demand while simultaneously justifying the auto-dependent sprawl it serves.

Lest we forget that such a project also takes years to finish and usually costs hundreds-of-millions of dollars — money that could be much better spent on transit improvements and maintenance of existing roadway facilities. Such policy is even more appalling within the context of climate change (especially with South Florida’s geography) and a threatened Everlgades ecosystem.

So, I encourage anyone who would like attend the open house tomorrow to go and voice your displeasure with any plan that will widen the Turnpike. Even better if you bring with you the studies I hyperlinked above to support your claims. Let these planners know that South Floridians are tired of wasting hundreds of millions of dollars on futile roadway projects that justify sprawl, do nothing to improve quality of life for Miami-Dade residents, and continue to leave commuters with little alternative to driving. Tell them you want to see sustainable alternatives that are transit-based.

The meeting information:

Thursday, September 27
5:30-7:30pm
Florida Dept. of Transportation District Six Auditorium
1000 NW 111th Ave, Miami

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