By Robert Poole
Those of us who spend our full-time efforts on transportation often despair that the average voter, the average reporter or editorial writer, or the average legislator, doesn’t know what we know.
If only they did, we believe, many more of them would support concepts like value pricing, high-occupancy toll lane networks, design-build, long-term concessions, etc.
So I’m especially pleased to tell you that two of my Reason colleagues, Ted Balaker and Sam Staley, have written a serious but accessible book about traffic congestion and what we can do about it. “The Road More Traveled” was released several weeks ago.
One of the book’s real strengths is its thoughtful discussion of how much mobility matters, both to people and to urban areas,and therefore how costly (not just in dollars) congestion really is.
A lot of research on these issues is being done as part of the Mobility Project, and Ted and Sam draw on that in these chapters.
I’m also partial to the chapters explaining why so much of what passes for conventional wisdom in transportation planning these days is “things that everybody knows that just ain’t so.”
But the real payoff comes in the book’s last five chapters, in which the authors draw on lessons from here and abroad to lay out a bold approach for attacking and dramatically reducing congestion, thereby increasing urban mobility and restoring vitality to impacted urban areas.
It will not surprise you to learn that this approach leans heavily on pricing, technology and construction.
The book carries impressive endorsements, including one from Mary Peters, before her recent appointment as secretary of transportation.
A quote from Joel Kotkin: “‘The Road More Traveled’ should be required reading not only for planners and their students, but also for anyone who loves cities and wants them to thrive as real places, not merely as museums, in the 21st century.”
Driving Restrictions, Air Quality
Mexico City pioneered the approach of restricting vehicle use to reduce air pollution, an approach subsequently emulated in Colombia, Chile and Brazil (and sometimes proposed in this country).
Implemented in 1989, Mexico City’s hoy no circula bans all vehicles with a specific last digit on their license plate from driving one weekday per week. It is evidently well enforced, and has definitely kept most of the targeted vehicles off the roads one day out of five.
But has it improved air quality?
That question is examined in some detail in a new paper by economist Lucas W. Davis of the University of Michigan.
Lucas used extensive data from the metro area’s network of emission-monitoring stations to compare the levels of five criteria pollutants before and after no circula plan went into effect. He finds no direct reductions in any of the pollutants.
A sharp decline in sulfur dioxide after 1992 is likely due to dramatic reductions in the sulfur content of diesel fuel in the early 1990s.
This finding raises several important questions, which Lucas goes on to explore. First, why didn’t the plan do what it was intended to do?
It apparently did cause some shifting of trips by owners of the restricted vehicles to late night or very early morning travel (outside the ban), but those trips (while lessening peak congestion) still polluted the air. There also was an increase in emissions on weekends, as people made trips then that they could not make on their driving-ban day.
What did not happen was a shift by drivers of those vehicles to subway or bus on the days when they could not drive.
In fact, both bus and subway lost riders in the years following implementation of the plan. What most drivers did turn to was taxicabs. Lucas finds evidence of a sharp increase in demand for taxis in the Mexico City market during 1990 to 1993.
And from data on the average age and condition of typical cabs, “taxis during this period were likely to be among the highest-emitting vehicles in Mexico City.”
Since the plan did not do what it was intended to do, and indeed, appears to have made air pollution worse in its early years, what should Mexico City (and others like it) do now? It turns out that in 1994, Mexico did what it should have done in the first place: It adopted U.S. emission standards for all new vehicles.
While this change will take several decades to have its full effect (thanks to fleet turnover), it is probably the most cost-effective approach.
The Mexico City experience is another reminder that even in a far less-affluent society than ours, the enormous benefits of personal mobility led to massive resistance to the attempt to shift people’s behavior away from door-to-door transportation at the time of their choosing.
Poole is director of transportation studies at the Reason Foundation in Los Angeles. His comments are excerpted from his regular column.
