Get breaking news alerts via email

Click here to manage your alerts
(Francisco Kjolseth | Tribune file photo) University of Utah students and employees board the red line train that connects the University of Utah to the rest of the light-rail network. A new U. study says the rail has decreased traffic in the 400/500 South corridor even as the area has grown through development.
University of Utah study: TRAX reduces car traffic
Light rail » It controls traffic growth and cuts volume below initial levels.
First Published Jul 03 2014 05:12 pm • Last Updated Jul 03 2014 09:56 pm

A new University of Utah study shows, for the first time, that adding a light rail line along a busy street in a growing area may not merely hold down future traffic growth, but can even reduce volume to below initial levels over time.

The study looked at effects of TRAX on 400 and 500 South in Salt Lake City, and "is the first study to document important effects of light rail transit on traffic volumes," said Reid Ewing, a professor of civil and metropolitan planning and lead author.

Join the Discussion
Post a Comment

"Since the University TRAX line opened, there has been increased development in the 400/500 South corridor, yet traffic on the street has actually declined," he said.

"Our calculations show that without the University TRAX line, there would be at least 9,300 more cars per day on 400/500 South, and possibly as many as 21,700 additional cars. The line avoids gridlock, as well as saves an additional 13 tons of toxic air pollutants" a year, Ewing said.

The study compared traffic, not only on 400 and 500 South but along nearby parallel roads, before and after the TRAX line was built. It also looked at neighborhood development. The study found that the area grew since TRAX was built, but road traffic did not.

"Instead, we found just the opposite. As the corridor became more developed over the decade — concurrent with the opening of TRAX — traffic actually declined," Ewing said.

While development along the corridor increased by 13 percent between 1999 and 2009, vehicle traffic volume decreased by an average 21,700 daily trips. Researchers said that saved 487,000 gallons of gasoline a year, and 9.5 million pounds of carbon-dioxide emissions.

Ewing said while that finding could be important, "We cannot guarantee that light rail would have the same effect on traffic at other locations" because of some unique characteristics of the 400/500 South corridor. Light rail there goes to the University of Utah, which is a major state employer and destination — and where faculty and students are given free passes to use TRAX and buses.

The report was issued recently by the National Institute for Transportation and Communities, and has been accepted for publication in the Journal of Public Transportation later this year.

Michael Allegra, president and CEO of the Utah Transit Agency, said the study helps show that TRAX to the university "has resulted in stabilized traffic flows, increased economic investment in the corridor and significant increases in transit ridership."

story continues below
story continues below

Copyright 2014 The Salt Lake Tribune. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.

Top Reader Comments Read All Comments Post a Comment
Click here to read all comments   Click here to post a comment

About Reader Comments

Reader comments on sltrib.com are the opinions of the writer, not The Salt Lake Tribune. We will delete comments containing obscenities, personal attacks and inappropriate or offensive remarks. Flagrant or repeat violators will be banned. If you see an objectionable comment, please alert us by clicking the arrow on the upper right side of the comment and selecting "Flag comment as inappropriate". If you've recently registered with Disqus or aren't seeing your comments immediately, you may need to verify your email address. To do so, visit disqus.com/account.
See more about comments here.
Staying Connected
Contests and Promotions
  • Search Obituaries
  • Place an Obituary

  • Search Cars
  • Search Homes
  • Search Jobs
  • Search Marketplace
  • Search Legal Notices

  • Other Services
  • Advertise With Us
  • Subscribe to the Newspaper
  • Access your e-Edition
  • Frequently Asked Questions
  • Contact a newsroom staff member
  • Access the Trib Archives
  • Privacy Policy
  • Missing your paper? Need to place your paper on vacation hold? For this and any other subscription related needs, click here or call 801.204.6100.