New “Induced Demand” Calculator Shows Exactly What Your City’s Freeway Expansion Will Encourage
Groundbreaking new calculator gives advocates the tools they need to instantly show the real impacts of proposed highway expansions in their communities – and the experts behind the project hope transport agencies will one day be forced to use it, too .
After the successful release of their Colorado induced demand calculator earlier this year, experts at the nonprofit RMI were inundated with requests from advocates across the country who wanted a similar tool to model the impacts of new road projects in their own cities. They therefore joined forces with Transportation for America, the National Resources Defense Council and a consortium of other partners to create the State Highway Induced Travel Frequency Calculator (SHIFT), which draws on formulas from decades of proven scientific literature to provide detailed, community-specific induced demand forecasts with the click of a button.
Defenders of sustainable transport and forward-thinking professionals have known at least 1932 that expanding highways to alleviate congestion almost always has the opposite effect, through a phenomenon known as ‘induced demand’. Without extensive training and resources, however, many have not been able to quickly quantify exactly how much extra driving a specific the project would encourage, or exactly how much all those new kilometers traveled by vehicles will make the climate crisis worse – so far.
And with $ 110 billion pledged to highway agencies shaping up as the most important item in the federal transportation bill on hold, the tool couldn’t be more timely.
“We really felt a sense of urgency to get out of this, especially with the prospect of a historically large investment in highway funding going to state DOTs who are used to ignoring the amount of driving and pollution that their highway projects will create, “said Carter Rubin, transportation strategist for NRDC and one of the collaborators who helped develop the calculator.
Rubin and the rest of the team behind the tool are hopeful advocates and professionals alike use it to highlight the real impacts of induced demand – a phenomenon experts say most traffic models rarely take into account.
“DOTs do a lot of traffic projections, but they are not asked to verify the accuracy of their past projections. were – and then they reuse those same faulty models, ”said Beth Osborne, director of Transportation for America and contributor to the tool. “Basically most of them don’t even consider that by creating more free assets people could abuse them. We are only preparing ourselves for inaccuracies.
Correcting these inaccuracies isn’t easy, but Osborne and his colleagues say cutting carbon emissions is absolutely essential, even as more electric cars hit the road.
“Even with a significant amount of electric vehicle adoption – a scenario we took into account, by the way – we would still see an increase in emissions through induced demand,” said Ben Holland, director at RMI and project manager. “Nationally, we need to reduce transport emissions by 45%, which is essentially the equivalent of putting 70 million electric vehicles on the road. and a 20% reduction in kilometers driven per vehicle per capita below 2019 levels. There is some optimism in some circles about our chances of reaching the first goal, but the second will be much more difficult.
In other words: “We have to reduce VMT, from yesterday,” Holland added. “And we need to stop making systemic investments and policies that essentially force people to drive more and more. “
Of course, greenhouse gas emissions are not the only negative externalities of major road projects that encourage more driving. Holland says future versions of the calculator may account for particulate pollution from things like tire and brake wear, which have proven disastrous to public health. induces the demand for strong, holistic arguments that help stop bad projects before they are built.
“There is so much damage associated with adding cars to the road,” Osborne adds. “The increase in driving means higher temperatures in the communities we have paved with, an increase in road fatalities, further blockages of economic opportunity, all of this inequality – and it also increases driving times. ride, which is exactly what DOT promises. habit happen when they say, “Let’s use your tax dollars to make this road bigger.” If they use this tool that we provide, they will no longer be able to make this promise in good faith.