The Environmental Assault on Mobility; J. Semmens

Air-quality planning across the nation is heavily dependent on air-quality "models." Unfortunately, these models are insuffi ciently connected to reality to be reliable measures of actual air pollution in any metropolitan area. In the models, emission estimates for vehicles are based on a "stan dard trip" from a 1969 Los Angeles survey. Whether such a "trip" would be represen tative of the types of trips taken in other urban centers across America seems dubi ous. Whether the conditions pertaining in 1969 are relevant for today, some 25 years later, is also questionable. The specific amounts of emissions for each vehicle are based on a sample of cars taken in Indiana. Whether emissions for these types of vehi cles might differ in the traffic and climatic conditions in other locations would seem a pertinent question, too. Dnfortunately, the federal bureaucrats in charge of this training session declined to address any of these questions. Even worse, Mr. Semmens is an economist with Laissez-Faire Institute in Chandler, Arizona.

an inquiry as to whether the air-quality monitoring program might be improved by a greater effort to actually measure quantities of pollutants was brushed aside. Appar ently, the officialsin charge of the air-quality monitoring program are not interested in attempting to actually measure pollution in the ambient air, nor to identify specific sources of emissions. Within the models, the alleged pollution reductions to be achieved by various mea sures are not evaluated for net impacts. That is, there is no analysis of the potential offsetting negative consequences of imple menting these measures. In the case of transit, for example, adding buses to the traffic stream would have some negative effects. The slower acceleration capabilities of buses and their frequent stops during peak-hour traffic significantly impede other traffic. This causes some increased vehicle emissions. But, since the model does not explicitly calculate or adjust for this effect, we do not know whether increasing the frequency and distances covered by buses decreases or increases pollution. During a question and answer session at the work shop, my inquiry on this issue was greeted with the cynical response that the data could be made to show whatever we wanted it to show. If this is true, then the models are useless as a guide to environmental policy making.

Most of the emphasis in current air quality 493 494 THE FREEMAN • AUGUST 1995 planning is aimed at discouraging travel. Many environmental planners at this train ing session expressed a preference for mak ing travel more inconvenient as a means of reducing trips and thereby cleaning the air. I find this approach discomforting. Mobility has a positive value to people. The ability to cover large distances in short periods of time enables people to enjoy wider employ ment opportunities and more access to the amenities that make for a better standard of living. Government policies that set out to reduce travel will lessen these positive benefits. Serving customers entails selling them what they want to buy. These customers should be charged a price that covers the full cost (including externalities, like pollution) to provide this service. While we want to promote cleaner air, a policy aimed at achieving this by reducing travel makes as much sense as a business seeking to reduce shoplifting by discouraging shoppers from entering the store. While restricting people's travel opportunities may satisfy the self righteous dictatorial proclivities of many en vironmental planners, it also serves to under mine the highly valued mobility that comes from a well-constructed and efficiently man aged highway system.

The potential impact of many of the "po litically acceptable" trip-reduction, pollu tion-mitigation measures (like expanding the public transit system) is pitifully small. In the Phoenix metropolitan region, for example, fewer than one percent of trips are made on public transit. Since transit trips are typically shorter than auto trips, the share of person-miles of travel for transit is even smaller. Given transit's tiny market share of total travel, expanding bus service would have a minuscule impact on pollu tion. A doubling of Phoenix bus service would cost taxpayers another $30 million per year. At best, this might lure one percent of drivers out of their cars. The meager potential of efforts to entice people out of their cars inspires some envi ronmental planners to promote ideas for forcing people out of their cars. Mandatory no-drive days are popular among bureaucrats. So, too, are punitive parking fees.

Strict land-use controls to compel people to live and work in high density zones are also viewed favorably. While these heavy handed measures might have a greater im pact on travel than subsidizing transit ser vices, their cost, in terms of sacrificed travel benefits, is an overlooked consequence. The good news is that we can make significant reductions in air pollution with out restricting travel. Since it is likely that the worst 10 percent of the vehicles cause 50 percent of the .pollution, a program to target these vehicles would appear to offer the best chance of meeting clean air goals. In this regard, mobile emissions testing is an obvious policy option. There is now a device on the market, the so-called "smog dog," designed to measure emissions from moving vehicles. This method of testing for emis sions is less expensive and more effective than the scheduled annual vehicle emissions inspections commonly employed in most urban areas.

Governments seriously concerned about vehicle contributions to air pollution ought to implement this kind of technology. In 1993, the Arizona Legislature passed a law mandating a pilot test of a mobile emissions enforcement program in the Phoenix met ropolitan area. This program took effect in January of 1995. A second obvious policy option is to use pricing to clear peak-hour trafficjams. Over half the trips during the peak hour are classified as "discretionary" (Le., non work trips). When the explicit price of using the roads during peak hours is zero there is little incentive for people who place a low value on their time to make these discre tionary trips at a different time of day. The result is a colossal waste of time and the creation of air pollution caused by rush-hour traffictieups. This may have been excusable when we lacked the means to overcome the problem. Now, with the automatic vehicle identification technology that is available, we have the ability to charge peak-hour users a peak-hour price while offering an off-peak discount to those who use the roads during periods when traffic is light.