Wednesday, September 19, 2007


Once each year, the Texas Transportation Institute (TTI) releases its Urban Mobility Report and the same old dance begins. Media, politicians and many others fret over the news ("Drivers waste 72 hours a year in their cars ..." from this morning's LA Times), and quickly wheel out favorite "solutions" (usually politicized pork projects, including rail transit and carpool lanes).

But what do we know? 1. Traffic congestion is a no-brainer; it is the default rationing mechanism because politicians are reluctant to price access. 2. It is remarkable how good traffic conditions are in spite of the policy failures; average journey-to-work times in the largest U.S. metros were less than 28 minutes at last census count (for solo auto trips). 3. These good news are explained by flexible land markets; most employers and employees find ways to locate within reasonable distances of each other. 4. The TTI index misses this phenomenon because it is constructed from metro area-wide average conditions; most traffic relief is found by relocations away from the metro area's most congested parts. 5. Planners want to shut down this safety valve by increasing land use controls, making land markets less flexible. 6. New transit projects cause increased highway congestion because they take money away from road construction. California has pioneered this approach.

Now loop back to #2 on this list.