Surface Transportation Innovations Newsletter

Surface Transportation Innovations #33

Topics include: why American cities don't work for transit; dueling technologies for future tolling; cleaner diesel trucks and the implications for transportation planning; feedback on the Winston/Langer paper; and quotable quotes.

In this issue:

Land Use and Transportation: Are U.S. Cities Different?

What is it about America that makes European-type mass transit so difficult to do here? Is it just pig-headedness that people won’t use it and continue to drive alone, despite serious congestion? Or is there something fundamentally different that makes transit much less suitable in U.S. metro areas?

That’s the question posed by urban economist Alain Bertaud, a European who now lives and works in this country, loves urban life, and uses mass transit. I recently came across his remarkable paper “Clearing the Air in Atlanta: Transit and Smart Growth or Conventional Economics?” published in the Journal of Urban Economics in 2003 (No. 54) and available at While it uses Atlanta as a case in point, its assessment is largely applicable to most U.S. metro areas, especially those outside the Northeast.

In response to high levels of congestion and air pollution, Bertaud recounts, Atlanta’s MPO developed new long-range transportation plans focused on reducing VMT via a twin-pronged strategy of large-scale investment in transit and fostering land-use changes to encourage transit-oriented development. Bertaud takes a careful look at how much these policies might be able to accomplish. His conclusion is that Atlanta’s spatial structure is such that “it is a geometrical impossibility for Atlanta to increase its density to reach the threshold level which would allow an effective operation of transit.”

To fully appreciate Bertaud’s paper, you must download it and peruse the graphs and charts. Several compare the densities of U.S. cities with those of overseas cities like Marseilles, London, Paris, Rio, and Barcelona where transit is a significant fraction of urban trip-making. In particular, his graphs show how concentrated (in both population and jobs) are the central business districts of transit-oriented cities abroad, compared with typical American ones. I was especially amazed by his chart showing the built-up areas of Atlanta and Barcelona at the same scale; with comparable populations in 1990 (2.5 to 2.8 million), Atlanta covers 4,280 sq. km.—compared with just 162 sq. km. for Barcelona. To provide the same level of metro accessibility in Atlanta as exists in Barcelona would require Atlanta to add 3,400 km. of metro line and 2,800 more stations.

He also looks into what happened to Atlanta’s population and jobs growth during the decade of the 1990s. The vast majority of both occurred far from the “central business district”, mostly within a belt between 30 and 45 km. from downtown. The actual CBD lost 10,000 jobs during that decade.

Bertaud then looks at the potential of two hypothetical densification strategies, crunching some numbers to see what it would take to bring the Atlanta metro area to the density threshold levels necessary to make transit accessible to significant numbers of people. The first estimates the amount of built-up area needed to achieve a density of 30 persons per hectare, a threshold level cited in several studies. Given projected population growth over 20 years, the built-up areas could be no more than 1,555 sq. km.—two-thirds less than exists today. Since that is a non-starter, he then calculates what would happen if planners banned any further expansion of the existing built-up area, forcing all growth to be “in-fill.” After 20 years, that would produce a density of only 11 persons per hectare, less than half the current density of Los Angeles and only one-third of the threshold level. Hence, he concludes, while New Urbanist neighborhoods may be nice things, such designs “will have no measurable impact on the spatial structure of Atlanta and therefore no impact on pollution and congestion.”

What should work, instead, is charging for highway use, combined with flexible mini-bus service. Transit would be recognized as a niche market for the transit dependent—a very different vision from today’s focus on moving heaven and hell to attract “choice riders.” Technology would solve the air pollution problem, via stringent tailpipe emission standards, fleet turnover, and the increasing use of alternative propulsion.

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What Kind of Open-Road Tolling Technology?

As transportation researchers look toward the possible longer-term replacement of fuel taxes with per-mile payment for road use, two current technologies vie for attention. One is digital short-range communication (DSRC) typified in the familiar E-ZPass, Sunpass, and Fastrak transponders that go on the windshield and are interrogated by overhead gantries. The other is based on GPS plus some form of wireless communications, referred to in Europe as GPS/GSM. The trade-offs between the two involve differences in cost for the on-board unit and for the necessary roadside equipment. In basic terms, the DSRC approach features simple, low-cost on-board units (indeed, as simple as the recently introduced “sticker tags” that cost only a few dollars) but requires a far-flung infrastructure of gantry-mounted equipment, potentially at every entrance and exit point on the toll roadway system. By contrast, the GPS/GSM approach features an expensive on-board unit, but at least potentially requires far less extensive roadside equipment, since the on-board unit keeps track of where the vehicle gets on and off.

The Winter 2006 issue of Tollways (published by the International Bridge, Tunnel & Turnpike Association) carried a useful article on these trade-offs, in a European context. The author is French consultant Francois Malbrunot. Using data from European toll systems using DSRC (most toll roads in France, Italy, and Spain) and GPS/GSM (the German truck tolling system), Malbrunot crunches the numbers for toll road systems of a range of sizes and activity levels.

I won’t get into all the details, and anyway the specific numbers may be too Europe-specific. But I think the broad conclusions are generalizable. Basically, he finds that GPS-based systems are better suited to systems with large mileage but relatively limited numbers of vehicles—such as long-distance trucks on a nationwide system. The more-costly GPS on-board units are better-suited to a professional fleet, and they can carry out a number of functions in addition to toll collection. But for systems involving millions of vehicles, especially urban toll roads, total system costs are much lower for DSRC systems.

These findings are based, of course, on today’s technologies. By the time the fuel tax is on its last legs as a viable highway funding source, perhaps 20+ years from now, we may have much less costly GPS-type systems which come built into all new cars. At that point, the on-road equipment costs of DSRC systems might overweigh the vehicle-related costs. But that’s a subject for another day.

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Clearing the Air on Future Diesel Truck Emissions

Diesel engines are dirty. Whether they power trucks, locomotives, or ships, they produce large amounts of particulate matter (PM) and nitrogen oxides (NOx), which are criteria pollutants of urban air quality. So it’s understandable that community groups and public officials are often opposed to highway projects that would facilitate continued use of trucks—such as the addition of toll truck lanes to urban freeways, as has been proposed in Atlanta and Los Angeles. But diesel trucks in America are on track to become much cleaner, and this has major implications for transportation planning.

The first step took place last month. As of June 1st, 80% of on-road diesel fuel must be “ultra-low-sulfur diesel” (ULSD). Retailers have until October 15th to comply with this rule. The point of the new regulation is to make diesel fuel compatible with the new 2007 diesel engine requirements that kick in next January 1st. When operated with ULSD, the new engines will produce 90% less PM emissions and 50% less NOx emissions than current diesel engines. Even tougher engine standards come into force starting in 2010.

Now obviously, those standards apply only to new diesel trucks. And because trucks with these engines are expected to cost more to operate (higher fuel cost, lower miles per gallon, increased maintenance cost), some trucking companies have been buying ahead, getting 2006 trucks while they still can. But even so, fleet turnover in coming years is going to make a major difference in emissions from trucks. In a presentation at the Transportation Research Board’s annual meeting last January, Mike Tunnell of the American Transportation Research Institute estimated the fleetwide impact, using EPA emission modeling. New trucks comprise roughly 6% of total trucks in any given year, so you get about 37% of the fleet consisting of the clean-diesel trucks within six years. In addition, the models assume that newer trucks are driven more than older trucks, with 10% of truck miles traveled by new trucks in year 1, and that same set of trucks accounting for 9% when they are a year old, 8% when two years old, etc. When he ran the numbers, Tunnell found that as early as 2010, the fleetwide impact of the 2007 emission standards would be a 32% reduction in PM and 17% reduction in NOx. And by 2015 there would be 63% less PM and 53% less NOx from diesel trucks overall. Future years would be even better, as the rest of the fleet turned over.

These changes have major implications for projects such as truck toll lanes. First, the environmental consequences of accommodating growth in diesel trucks via such new infrastructure must be based on accurate modeling of future emissions—and those results must be communicated to community groups concerned about health issues and to elected officials who want to do the right thing. Historical diesel emissions, and images of clouds of black soot, are irrelevant to a project that will likely take 5 or 6 years to get approved and another 3 or 4 years to build. What’s relevant is the emissions of the truck fleet from 2015 onward.

Second, opponents of truck lanes (e.g., of the proposed toll truckway to serve the ports of Los Angeles and Long Beach) sometimes argue that such a project would be unnecessary if only more containers were forced onto rail lines instead of roadways. Apart from questions of commercial feasibility (do those rail lines go where the containers need to go, and match just-in-time delivery requirements?), this argument ignores the very real emissions trade-offs involved. In Southern California, for examples, diesel locomotives emit 37 tons per day of NOx, more than the combined emissions of the area’s 320 largest industrial sources (oil refineries, power plants, etc.). And locomotive emissions are “untouchable” by most state and local emission rules (since railroads are federally regulated as interstate commerce). Thus, the practical reality is that during the same decade when truck diesel emissions will be trending dramatically downward, diesel locomotive emissions will remain high.

Therefore, environmental concerns should not be an obstacle to the development of truck toll lanes.

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Feedback on the Winston & Langer Paper

My write-up last month on the recent paper by Cliff Winston and Ashley Langer led to quite a bit of feedback. So I welcome the opportunity to return to this subject. Their paper is an econometric exercise looking to see how much impact highway spending has on reducing congestion. If you recall the write-up, my main focus was that this paper could easily be used by those opposed to expanding highway capacity, who would claim that it reinforced their view that adding capacity is ineffective in reducing congestion.

Winston’s main response was to defend the paper’s methodology by pointing out that they had taken note of most of my objections in the paper itself. For example, he notes that the paper acknowledges that very little capital spending is used for new road capacity, and that when they tested the impact of separately considering capital versus maintenance expenditures, there was little statistical difference in the (already small) impact on congestion costs. Fair enough. I apologize for not being clear enough about these methodological points.

On the issue of comparing congestion-reduction benefits with highway spending in the same year, Winston says they tested a lagged effect and found that it made no difference. In defending against my point that they should have measured multi-year congestion-reduction benefits, he notes that the first-year effect was so small that adding future-year benefits would not have added much. But that point further serves to indict the status quo, which allocates so little to actual capacity expansion while still managing to spend a fortune on highways.

So my real quarrel is not with the paper or its authors, who used accepted econometric techniques and measured what was available to measure. Rather, it is with a politicized process of allocating resources not to where they would deliver the greatest value for highway customers but to where the political benefits are greatest. And this, indeed, is a point I praised the paper for making. I’m also in general agreement with Winston on the importance of both pricing and privatization in leading to more productive investment in our highway system.

I’m still very concerned that this paper will be used by opponents of auto-mobility to advance their cause. To say (as the authors do) that increased investment in the highway system is not a good way to reduce congestion is a far broader conclusion that what the paper actually found. It also flies in the face of decades of findings by TTI (noted in the first article above) that those metro areas that have come closest to keeping highway capacity in step with traffic growth have had the least increase in congestion.

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Quotable Quotes

Mineta’s Parting Words on Congestion

“We can and must address the congestion that is so pervasive in today’s America before it seriously undermines our economic competitiveness and quality of life. Nationwide, the economic price tag of congestion is already a whopping $200 billion a year . . . But we do not have to resign ourselves to live with congestion. To the contrary, a little over a month ago I announced a plan that can begin to seriously reduce traffic congestion nationwide—now and not 10 or 15 nears down the road—if we have the leadership and political will at all levels of government to see it through.

“Some of what we have suggested will be controversial. It will necessitate a cultural change to move from a government-monopoly model for much of our transportation infrastructure toward acceptance of the private sector and market forces.

“If we can fix the policy problems, I am confident that the conditions will be ripe for substantial investment. Virtually every major financial institution on Wall Street has created—or is in the process of creating—an infrastructure fund with transportation as a major component. They correctly recognize the enormous potential in American infrastructure. And it is imperative that future transportation decision-makers continue to foster this interest, not take steps to discourage it.

“History may well reflect back on this as one of the defining public policy debates of our time—as consequential as the one that gave birth to the Interstate Highway System some 50 years ago. And the business community must be active participants.

“Finding a way to tackle congestion more meaningfully and successfully is not a problem for some future generation. It is an urgent challenge for today’s leaders.”

-Norman Mineta, Farewell Remarks, U.S. Chamber of Commerce, July 6, 2006

Potential of Public-Private Partnerships

“I do see that as a hot-ticket item. Probably when you look at surface transportation, the most exciting thing to come out of the Department of Transportation besides money has been the introduction of public-private partnerships in this country.”

-Kenneth Mead, former Inspector General, U.S. Department of Transportation, quoted in Traffic World, July 3, 2006.

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