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State Highway Induced Frequency of Travel and Climate Change in Texas

Summary of articles by Rachel Albright, Tarrant Transit Alliance

Image of traffic

As the United States grapples with meaningful action on climate change, much emphasis has been placed on the transportation sector, and with good reason. Transportation accounts for 29% of the country's greenhouse gas emissions, the most of any sector. Additionally, “The largest sources of transportation-related greenhouse gas emissions include passenger cars, medium- and heavy-duty trucks, and light-duty trucks, including sport utility vehicles, pickup trucks, and minivans. These sources account for over half of the emissions from the transportation sector.” studies have shown that private autos, or “single-occupancy vehicles,” produce significantly more CO2 Emissions per passenger mile

Our Reliance on Personal Vehicles Increases Vehicle Miles Traveled (VMT)

An article published by RMI, a non-partisan, non-profit organization that works to transform global energy systems across the real economy, outlines the importance of the transportation industry and future choices for our community in the fight for cleaner air and a more environmentally-friendly future.

Our reliance on personal vehicles helps rack up a staggering three trillion vehicle miles traveled (VMT) each year. Additionally, our highway system has segregated populations, heightening long-standing injustices. At the same time, high costs of living and limited housing options continue to facilitate sprawl away from city centers.

To limit global warming to 1.5°C, the U.S. must reduce VMT by 20% before the decade's end. Elected officials and transportation professionals must start seriously considering strategies that can reduce the amount of driving that takes place. Transportation investments overwhelmingly favor personal vehicles over public transit and other non-drivers. Innovative growth development strategies can help remedy this disconnect by co-locating residential density with popular destinations. Infill development and transit-oriented development (TOD) promote more compact, walkable urban communities.

Road Expansion Projects Generate More Traffic.

Since 1980, total lane-miles in urban and suburban areas have doubled. Evidence continues to mount that Increased highway projects exacerbate traffic and associated pollution. Road expansion projects achieve only fleeting benefits while generating more traffic. This increase in traffic increases climate pollution worsens local air quality and leads to more road crashes. Forward-looking transportation investments should be aimed at reducing traffic and boosting accessibility, including public transportation investment.

Texas is Behind the Curve

Sadly, Texas falls behind when it comes to multi-modal transportation planning and investment. Decision-makers systemically overstate the benefits of road expansion, continuing a cycle of growth. The models that agencies depend on have a poor track record of success. However, they never look backward to consider their accuracy or how they can be improved.

Transportation plans are often crafted looking 20+ years in the future. As we look at opportunities to improve air quality and livability in North Texas, how much of the proposed projects coming down the pipeline by TxDOT and NCTCOG focus on modal shifts to improve air quality, and how much induced demand occurs?

For example, As this Transportation For America Article Highlights - in 2002, TxDOT "predicted that average daily traffic (ADT) on I-35 through downtown Austin would be 330,000 daily vehicles by 2020. The reality wasn't even close: Actual totals in 2019 were only 201,000 daily trips... in 2016, with the state totally ignoring how wildly inaccurate their current projections were turning out to be, they projected 'that total VMT on I-35 in the Austin area would increase by 50% by 2040'...All it's going to cost taxpayers is $5 billion to widen I-35 right through downtown. If the state follows through on this staggeringly expensive project, they'd be creating millions of new trips and increasing pollution, all while failing to make a dent in congestion over the long term and wiping out hundreds of acres of some of the most valuable land in the entire state."

It is worth noting that NCTCOG is not an implementation organization – agencies submit their projects to them. This means that it is up to agencies like TxDOT and elected officials to encourage projects that focus on modal shifts and that improve air quality. It also means that we need more support (and funding) for modal shifts at the Texas State and regional planning levels. We will explore this in future articles.

Check Out the SHIFT Calculator Yourself!

We encourage you to check out the SHIFT Calculator (State Highway Induced Frequency of Travel). This new, rigorously vetted calculator produced by RMI, the Natural Resources Defense Council, and Transportation for America provides more accurate and transparent data about increases in driving and pollution, as well as the other impacts of highway expansions.

"Our hope is that advocates, local governments, and anyone who cares about finally getting more accurate and transparent data about increases in driving and pollution will use this new tool to hold their transportation agencies to account. And we want transportation agencies to use it to bring a fuller picture to their current transportation modeling that leads them to 'solutions' that fail to address congestion, divide neighborhoods, increase pollution, devastate nearby communities, and fail to meaningfully improve our access to jobs and services."

You can check out the SHIFT Calculator below:


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