Surface Transportation Innovations Newsletter

Surface Transportation Innovations #18

Topics include: Longer Combination Vehicles (LCVs), electronic toll tag technology, adaptive cruise control to help reduce traffic congestion, and other breaking news stories.

In this issue:

Getting More Payload from Fewer Trucks

What if we could make a single policy change that would take 25% of big trucks off the highways, reduce fuel use and emissions by 12%, and save shippers about $2 billion per year? Those results are among those estimated for 13 western states that already allow double- or triple-trailer rigs to operate, if they would simply unify their size and weight regulations so that twin 48-foot trailers could operate in all of them. They come from a US Department of Transportation report, dated April 2004, called the Western Uniformity Scenario Analysis, done in response to a request from the Western Governors’ Association.

Long doubles and triples are known as Longer Combination Vehicles (LCVs). This kind of big rig permits a single driver to haul considerably more payload, economizing on labor as well as fuel costs. The 1991 ISTEA legislation created a federal freeze on any further liberalization of state truck size and weight regulations, so the 13 western states that allow LCVs (all except AZ, CA, NM, and TX) have a crazy-quilt of different regulations, which greatly reduces the gains that could be had from region-wide long-haul use of LCVs.

The DOT study looked at region-wide use of 45-ft. and 48-ft. double-trailer rigs. It compared a base case (business as usual) with a scenario in which these types of rigs were allowed uniformly in the 13-state region. Because of significant substitution of more-productive LCV rigs for conventional tractor-trailer rigs, total truck vehicle miles traveled (VMT) would be 25% less by 2010 under the scenario modeled. Fuel use and emissions would be 12% less. And interestingly, the model predicts less than 1% traffic shift from rail to truck (which has always been a major fear of the railroad industry).

To be sure, there are no free lunches. Using more LCVs would have impacts on the highway system, and the study attempts to quantify them. Incremental costs of bridge improvements in the 13 states would be between $2.3 and $4.1 billion. Another $776 million would be needed for geometric improvements to lanes and interchanges, due to the longer rigs. But pavements would actually last somewhat longer, saving $2.8 billion, due to (1) 25% less truck VMT, and (2) no change in axle load limits. But since shipping costs would go down by $2 billion per year, there would certainly be room to charge for the needed highway improvements (a point the DOT report does not make).

And like previous DOT size & weight studies, this one is inconclusive about the controversial issue of the net safety impact of having fewer total trucks but a lot more of them LCVs in this region.

All of which further underscores the advantages of Reason’s Toll Truckways concept: developing barrier-separated truckways with pavement, geometrics, and bridges designed specifically for LCVs, built mostly along existing Interstate corridors. We have new work under way crunching the numbers for large-scale, mostly urban Toll Truckways for Northern and Southern California. That report will be out sometime this fall, and its publication will be highlighted in this newsletter.

[Note: so far the DOT study has not yet appeared on FHWA’s truck size & weight studies web page, but if you’d like access to it, send me an email.]

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Which Way for Electronic Toll Tags?

Two very different new technologies are emerging for the on-vehicle transponder tags used for electronic toll collection. Today’s standard is a battery-powered tag mounted on the inside of the windshield with Velcro (so it can be moved from one car to another in a household), operating in the 902-928 MHz frequency band. Around 15 million of these transponders are now in use, costing $25-30 apiece. But new technologies portend big changes. On one end are new “sticker tags,” so cheap that they could be given away. At the other end are much more expensive, multi-function tags that may or may not see widespread use.

Sticker tags emerged from the need to speed large numbers of vehicles through border crossings in the wake of 9/11. Thanks to funding from the Dept. of Homeland Security, TransCore developed and is supplying $10 sticker tags, as thin as a credit card, that stick permanently to the windshield. Operating in the existing 902-928 MHz band, they need no battery, receiving enough power from the interrogation signal to bleep back their encoded ID number. Over 250,000 are already in service on vehicles using 94 border-crossing inspection lanes, under the Fast and Secure Trade (FAST) program. And a few months ago, Puerto Rico introduced these sticker tags for electronic toll collection on the island’s toll roads and bridges. Motorists snapped up 60,000 tags in the program’s first 10 weeks, so they already account for some 30% of toll transactions at some plazas, reports Peter Samuel in ITS International’s July/August issue. Peter also reports that the Texas Turnpike Authority is considering giving away sticker tags to encourage electronic toll usage on the huge new system of toll roads being introduced in the Austin area.

But at the other end of the spectrum, the US DOT is encouraging development of a next-generation transponder in the 5.9 GHz frequency range. The four major toll tag vendors have set up the 5.9GHz DSRC Industry Consortium for research & development of prototype systems. The design provides for much greater range and data transfer rates than needed for electronic tolling, since the DOT sees a large number of potential vehicle-to-roadside communications functions such a tag could perform, especially in the safety area. No cost estimates are available, but they will clearly be a lot more expensive than today’s standard toll tags, let alone the new sticker tags. That’s why some apparently are hoping the auto industry can be persuaded to include 5.9GHz tags as original equipment in all new cars within the next 10 years.

Interestingly, the cost (hence affordability) of transponders may yet become a political issue. When I took part in a workshop introducing Managed Lanes (and hence electronic value pricing) to the board of the MPO in Miami-Dade County in June, one of the questions that came up was how affordable the tags would be to Miami’s lower-income drivers. Fortunately, Jim Ely of Florida’s Turnpike was prepared for the question, answering by introducing the Puerto Rico-type sticker tag as something they are seriously considering.

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Adaptive Cruise Control: a New Approach to Congestion Management?

Several researchers have recently suggested that adaptive cruise control (ACC) may help reduce traffic congestion, by limiting the extent to which human over-reaction to brake-lights ahead causes a cascade of braking that pushes traffic into unstable stop-and-go conditions.

If you’re like me and don’t yet own a car equipped with ACC, a brief description may be in order. Adaptive cruise control uses radar to monitor the distance between your car and the one ahead of it. Computer control applies the brakes when needed to maintain a safe distance, but can do so without the normal human lag-time (of nearly one second). In extensive simulations, this difference in reaction time turns out to make a big difference. For example, Michigan physicist Craig Davis finds that on a single-lane road, even if only 20% of all cars are equipped with ACC, the transition to unstable, stop-and-go flow is eliminated. Unfortunately, things are not as simple on multi-lane freeways. Under some circumstances, reports The Economist, ACC can even make congestion work. But by reducing the amount of headway built into the software (i.e., letting cars operate closer together than most of us feel comfortable doing), other researchers report more promising results in freeway simulations.

To the best of my knowledge, there’s been no significant on-road testing to validate these simulation modeling exercises. But as ACC moves into a broader range of new cars this decade, and normal fleet turnover occurs, we may soon begin to observe whether ACC can live up to the predictions of the models. Thus far, the only means we know actually works to control real-world congestion is market pricing. But perhaps ACC will be able to give it a helping hand.

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Which Clean Cars (if any) Deserve Special Treatment?

Since the California bill to permit (single-occupant) hybrid cars to use HOV lanes is still pending as I write, I hope you’ll excuse me for once more taking up the absurdity of singling out hybrids for special treatment. Yes, I think the Toyota Prius is neat, and several of my friends and colleagues have them and love them. But if you want to talk about clean cars, what about new models of the BMW 325i, the Honda Accord LX and EX, Toyota Camry LE, SE, and XLE, and the Volkswagen Jetta GL and GLS? These are among the 31 makes and models that meet California’s extremely stringent Partial Zero Emission Vehicle (PZEV) standard. To meet the standards, they must emit 90% less hydrocarbons, nitrogen oxides, and carbon monoxide than conventional cars sold in California. That makes them so clean that it would take 590 of them to equal the hydrocarbon emissions of a 1970 car. To do this, they have better catalytic converters and zero evaporative emissions. Plus they must have a 15-year or 150,000-mile warranty on their emission-control system.

The PZEV standard came about when California’s Air Resources Board realized that its electric-vehicle mandate was unrealistic; practical, user-friendly EVs simply cannot be made with today’s battery technology. But rather than simply throwing out the mandate, the ARB allowed auto companies to get EV credits for building hybrids or PZEVs. And that turns out to be do-able with today’s technology. The ARB estimates that 140,000 PZEVs will be on California highways by the end of 2004, and 4 million by 2010.

Joe Nordbeck, director of the Center for Environmental Research & Testing at UC Riverside, has been testing PZEVs for several years. He completed a study last fall concluding that even greater Los Angeles will be able to meet federal clean-air standards as long as enough PZEVs are sold in coming years. “With PZEVs, the light-duty-vehicle problem has pretty much been solved,” he told the Washington Times last month. “Their emissions are almost below detection level.” And Massachusetts, New York, and Vermont have also adopted California’s PZEV standards.

So if clean-air goals can be accomplished by mass-marketed PZEVs, why should public policy bend over backwards to give special privileges to hybrids? Especially when giving hybrids access to HOV lanes threatens to overload them, destroying their effectiveness today and creating yet another interest group that will resist their conversion into HOT lanes?

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Speaking Engagements

This fall is shaping up as a very busy period for me. In addition to releasing a major new Reason policy study on how tolled mega-projects (including Toll Truckways) can help address California’s transportation funding crisis, I will be speaking at a number of conferences. Among them are the following:

  • Sep. 30: Independence Institute, Denver (HOT Networks)
  • Oct. 8: Humphrey Institute, Minneapolis (BRT and HOT lanes)
  • Oct. 12: Texas DOT, Texas A&M (toll roads)
  • Oct. 13: Team Florida, Miami (Managed Lanes)
  • Oct. 20: NCPPP, Sacramento (tolls and project finance)
  • Oct. 26: UCLA, Lake Arrowhead (Toll Truckways)
  • Nov.18-19: TRB Fuel Tax Committee, Washington, DC (meeting)
  • Dec. 8-9: ARTBA PPV Conference, Washington, DC (Toll Truckways)

Hope to see you at one or more of these!

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In the last issue, I wrote about an important new paper on the wide range of commuters’ value of time, based in part on analysis of data from the 91 Express Lanes in Orange County, co-authored by friend and colleague Ken Small. Ken tells me you can find one version of this paper as working paper #546 at the following site:

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