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In the view of such planners, and many others concerned about traffic congestion and automobile pollution, nothing short of a comprehensive network of government controls can solve urban transportation problems. It is the private automobile that is the problem, they charge. If enough of us will not voluntarily renounce its use, then our freedom to choose times, places, and modes of travel-and even to choose where we will live and work-must be restricted.
In the face of the massive and costly failure of the traditional political “fixes” and the drastic implications of envisioned control of people’s lives, it seems warranted to step back and consider an alternative. This alternative has played well in academic journals for years but has been steadfastly ignored by politicians and planners. .It relies on some basic facts about people’s use of any resource-including roadway space.
WHAT IS CONGESTION?
Congestion is a form of queuing, an economic phenomenon that can occur whenever the demand for a good, at a given time and place, exceeds the quantity that is supplied. Some expressway congestion is transitory, of course, arising from interruptions of the traffic flow due to accidents,
road maintenance, or other temporary conditions. Some is site-specific, associated with approaches to airports, shopping centers, and the like. But the most typical and recurring variety is caused by weekday commuters, whose demand for road space regularly outstrips the available supply, often congesting whole metropolitan areas.
On any expressway, only so many vehicles, traveling at 50-55 miles per hour, can pass by a given point in an hour’s time. When more than that optimal number attempt to use a particular stretch of roadway, average speeds are reduced, increasing the time it takes to drive that stretch. In other words, the average cost of roadway use, in time and operating expense, rises when congestion sets in.
There’s a crucial point about the way these costs rise, though, and it can be clarified by a simple example. Suppose that any number of cars up to 999 per hour can drive a particular roadway segment in 20 minutes at normal speed. If an additional driver, car number 1,000, enters the roadway, it will take each car 21 minutes to pass through this stretch. Because the added vehicle causes the roadway to become slightly congested, its driver incurs a time-cost one minute
greater than if he had driven at some other time. One minute is negligible to this driver, of course, and to each of the other 999 drivers whose travel time he has caused to rise by the same amount. Yet the addition to the total time-cost generated by this one additional vehicle is 1,000 minutes (one minute times 1,000 drivers). That’s 16.67 hours!
Enter now drivers number 1,001, 1,002, and so on, and the same thing happens. And the situation gets worse in another way: each additional vehicle causes a greater and greater increase in the time it takes each driver to travel this road segment. The more crowded the roadway already is, the greater the cost engendered by one more driver.
The actual costs, though, are not visible to the additional drivers. Place yourself in the shoes of driver number 1,000. For you, the decision say to drive. now or at some other time when the road space is less in demand is a choice between 20 and 21 minutes. Since you don’t bear the actual additional cost of your decision-the 16.67 hours-there’s no way you can even perceive what it is.
The costs of goods and services are normally reflected in their prices (otherwise the providers would go out of business), and purchases are made only when buyers believe that the benefits to them are at least equal to the prices. The virtue of this system is that resources will be devoted to providing a good or service only so long as the benefits to be gained, as evidenced by consumers’ willingness to pay, are not outstripped by the cost. The happy result, in economists’ talk, is an efficient allocation of resources.
Roadway space, though, is generally provided as a free good. Construction and maintenance, of course, are paid for through taxes and registration fees, but the use of roads is not priced. While there can be little doubt that the benefits gained by drivers 1,001, 1,002, and so on from using the expressway are nowhere near as high as the actual costs generated by that use, those are not the costs they face. The inevitable result is heavier- than-optimal traffic at the times and places of greatest demand-or an inefficient use of this particular resource, roadway space.
The consequences of this inefficiency can be staggering. Daily congestion costs for Los Angeles-area freeways have been conservatively estimated at 100,000 hours. If average driving time is valued at $4.50 per hour, at a typical vehicle occupancy of 1.1, these direct congestion costs come to $118.8 million per year. The greatest share of these costs is concentrated in the weekday morning and afternoon peaks, when traffic is 50 percent greater than during other daylight hours.
Obviously, increased travel time is by no means the only negative effect of congestion. Much air pollution (particularly airborne carbon monoxide) occurs primarily in areas of high traffic density and follows the same spatial and temporal patterns as expressway congestion. In Los Angeles, 40 percent of all vehicular smog originates during the morning rush hour, and it has been estimated that cutting peak-hour traffic by one-fourth would lead to a seven percent reduction in total smog. Noise pollution, too, is closely associated with heavy traffic and is known to reduce property values near congested routes. The total of these direct and indirect costs has not been, and probably cannot be, measured but could be safely said to amount to several billions of dollars annually, nationwide.
WHY NOT PRICING?