On Thursday, TxDOT celebrated the completion of new lanes opening along the Gulf Freeway between Beltway 8 and Bay Area Boulevard, and more expansion is coming. But will it really help ease traffic congestion?
TxDOT numbers show the stretch of I-45 between Beltway 8 and NASA Parkway is the 25th-most congested highway segment in the state. Now they’re looking to widen the freeway just south from NASA Parkway to FM 518, forking over $112.3 million between 2017 and 2020 to “improve mobility on a heavily traveled hurricane evacuation route”, with the goal to eventually widen I-45 all the way to Galveston.
So KHOU wanted to verify: Does building more lanes help ease congestion in the long run?
Our Verify team used two sources: First, Matthew Turner of Brown University. He published one of the biggest studies on this issue, studying traffic in dozens of cities across the country, including Houston, over a 20-year period.
Secondly, our team used a report from the Texas A&M Transportation Institute put together for state lawmakers and the transportation commission on how to solve gridlock.
Turner’s study found as the percentage of freeway lanes went up, the percentage of cars on those freeways went up at the exact same rate. He points to "Carmaggedon," the massive LA freeway widening project from 2011. He says 18 months after that project was finished, traffic levels were back up to the same level as before it was built.
Why is that? It’s similar to a theme in the film, "Field of Dreams": if you build it they will come. Turner says more roads equals more people moving farther out, and more people taking trips they used to put off to avoid traffic.
The TTI study found more lanes can help in the short term, but agreed long term cities can’t build their way out of the problem.
“It’s not just something you can dump on TxDOT and the city,” said Tim Lomax, a researcher and one of the TTI study’s authors, during an interview produced by TTI. “It’s something everybody plays a role in.”
So what does the study recommend for a growing state like Texas? Anything and everything from public transportation, carpooling, working from home, to toll lanes.
Turner says after studying four options for relieving gridlock --- building lanes, building public transportation, building more dense housing, and adding tolls ---- he found the only option that makes a significant difference in easing gridlock is the toll option.
London and Singapore have implemented “congestion pricing,” charging drivers to enter a congested area during busy times like rush hour. The idea was proposed for New York City but never became reality.
Turner says the challenge, especially in a tax-averse state like Texas, is getting both governments and citizens on board with what’s basically a new tax.
So, KHOU can verify that adding lanes can help alleviate gridlock in the short term, but typically not in the long term.
Matthew Turner, Brown University and author of The Fundamental Law of Road Congestion: Evidence from US Cities study
Texas A&M Transportation Institute report