You Can’t Pave Your Way Out of Congestion !

Traffic Congestion – Kenya

“Building more lanes to cure congestion

is like loosening your belt to cure obesity.”

1) There is now overwhelming evidence, including a nationwide study of 70 metropolitan areas over 15 years (Texas Transportation Institute), and another California specific study (Hansen 1995, which included Monterey County) that when an area is congested – additional lanes or roads do not provide congestion relief.

2) It is also well documented that additional lanes increase traffic, and that new highways create demand for travel and expansion by their very existence.

3) Further experience shows “When road capacity shrinks – So Can Traffic;” traffic congestion goes down !

  • So, when a road is congested, adding more lanes or roads will not relieve congestion, but will likely increase traffic.
  • When a road is congested the only way to relieve congestion is not by building more roads, but by reducing land use – or paradoxically by closing roads.




1. “An Analysis of the Relationship Between Highway Expansion and Congestion in Metropolitan Areas”, Nov 1998, Texas Transportation Institute, Surface Transportation Policy Project.

2. “Do New Highways Generate Traffic?” Fall 1995, M. Hansen, Access – UC Berkeley Engineering.

3. In January 1997 US Federal District Court, Judge Suzanne B. Conlon for the Northern District of Illinois, Opinion wrote:

“Highways create demand for travel and expansion by their very existence.” Swain v. Brinegar, 517 F.2d 766, 777 (7th Cir.1975); Def. 12 (M) Par. 86. “However the final impact statement in this case relies on the implausible assumption that the same level of transportation needs will exist whether or not the toll road is constructed.” “[FHWA’s] decision in this regard was arbitrary and capricious. 5 USC Sec 706(2)(a).”

4. San Francisco’s Central Freeway in 1996, New York’s West Side Highway 1988 in Auto Free Times Winter 1996-97; “Remove it and They Will Disappear” by Jill Kruse STTP Research Coordinator, 1998)


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3 Responses to You Can’t Pave Your Way Out of Congestion !

  1. R S F says:

    The traffic congestion picture used is not Los Angeles, it’s Kenya. It’s curious that the studies referenced apparently were not read by the poster. Perhaps he missed: “Over the last several decades and in many corners of America, claims of induced demand have stopped highway projects in their tracks. This is wrong-headed.”

    The huge elephant in the room, missed by a couple of the papers is this: Yes, when extra lanes are added, more cars flock to that roadway. But here’s what get missed: Those cars came from somewhere. The roadways/places they came from had a proportionate DECREASE in their congestion.

    I have an easy way to prove much of this is wrong. Anyone who really thinks added lanes make no difference, or that they make traffic worse should do this little test. Go out to the congested roadway near you and stall your car in one of the lanes. Can you guess the result? Hint: It won’t be LESS congestion.

    • DavidEnv says:

      It is actually the commenter who either failed to read the papers or understand them. All the research consistently shows that when lanes are reducedPLANNED driving is also reduced.

      The commenter fails to appreciate the difference between additional (or less) planned vehicle use and temporarily re-routed vehicle use – after driving has already started.

      It is the difference between extreme short-term loss of lanes (car accident or stall which cannot change a planned driving event) and medium (weeks) to long term change in road availability and how less lane/road availability reduces planned driving.

      The commenter was right about one thing. We lost the LA traffic photograph, and I too hastily replaced it with another – without changing the caption. Will fix that soon.

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