Skip to Content
Streetsblog California home
Streetsblog California home
Log In
Damien Talks

DamienTalks 40 – Michael Manville on Automatic Road Widenings

It's been a while since we recorded a #DamienTalks specifically for the California website, but now we're back with a good one. In this week's edition, Damien Talks with Michael Manville, a professor and researcher at UCLA.

#DamienTalks

Manville has hit a bit of Livable Streets fame with an article he wrote for the Journal of Transportation and Land Use. In that article, he outlines why laws requiring developers to invest in road widening to "mitigate" traffic created by their development don't actually do anything to improve traffic flow locally or regionally.

Almost nobody who understands transportation planning believes that these requirements do anything to improve traffic flow--yet these laws persist.

Manville doesn't only debunk the theory behind the laws, but also offers a solution...should policy makers heed his call.

You can read "Automatic street widening: Evidence from a highway dedication law" at the Journal of Transportation and Land Use here, and a summary of the article from Streetsblog USA here.

We’re always looking for sponsors, show ideas, and feedback. You can contact me at damien@streetsblog.org, at twitter @damientypes, online at Streetsblog California or on Facebook at StreetsblogCA.

Stay in touch

Sign up for our free newsletter

More from Streetsblog California

CA High-Speed Rail Approves Large Cost Overrun, Legislation Moves to Empower Inspector General, Unhinged Critics Criticize

The California Post tabloid newspaper arrives, and so does sensationalized criticism of California High-Speed Rail.

February 12, 2026

Thursday’s Headlines

New bike lanes, new Coaster service, and more Vision Zero follies.

February 12, 2026

Talking Headways Podcast: Concrete Doesn’t Spend Money, People Do

Dr. Lawrence Frank shows how the decisions we make about the built environment are a symbol of why the world is so f'd up. A very special edition of Talking Headways.

February 12, 2026

Why Does Trump Wants To Punish Cities For Free Buses?

Hint: it's probably not to make anyone's transportation network better!

February 11, 2026

Eyes on the Street: Shrinking the Gap Between Fruitvale BART and the Cross-Alameda Trail

But there will remain a safety gap on the Fruitvale Avenue bridge.

February 11, 2026

L.A. Seeks Input on Proposed Speed Camera Locations

L.A. is planning 125 speed camera systems citywide - location criteria includes histories of speeding/crashes/racing, areas with concentrated vulnerable populations, etc.

February 11, 2026
See all posts