Congestion

Light rail and traffic congestion: A Sympathetic Argument.

Common sense dictates that the first goal of any transportation initiative should be to minimize the time and expense it takes for the average commuter to reach his or her destination. The primary purpose for the construction of new roads is therefore the reduction (or more commonly, prevention) of traffic congestion. It stands to reason that light rail, offered as an alternative to automotive travel, should accomplish the same purpose. The fact that rail is more expensive than the construction of new roads (by variously reported factors) and yet has not been shown to reduce congestion at anything approaching a commeasurate rate is often used by critics to demonstrate its economic inefficiency.
It appears to be the case (and is often argued by critics) that in the vast majority of U.S. cases when a new LRT system opens, traffic congestion throughout the metropolitan area sees a decrease of less than 1% which dissipates within a matter of months. However, there are two major irrelevancies contained in this kind of argument.

First, there is little point in measuring changes in congestion in terms of an entire metropolitan area with regard to light rail that serves particular routes. Figures supplied by critics for alternate plans such as adding freeway lanes are not typically measured in this way. As lightrailnow.org points out, "It's silly to measure how much any road, bus, or rail-line touches the population because we would then argue that nothing is justified. Imagine for a moment that in order to justify a new road or bus line, 'at least 30%' of Austinites would have to sign up to use it everyday. Nothing would get built because it would require that we all live in about the same area and want to go to the same place, using the same road, everyday."

In fact, the main aim of the Hiawatha Line is to reduce congestion and stimulate development along a particular corridor. It will reduce traffic along Highway 55 to a significant degree, thus having a tangible effect on the lives of people who live along the route. Figures that claim the line will be no faster than automobile transport do not take congested conditions (rush hour) into account, even though this is when most automobile trips occur. While only 10% of Metro area jobs are located downtown and thus made easily accessible by the Hiawatha line, the long term aim of the line (similarly to most any LRT project) is to oppose sprawl by revitalizing downtown Minneapolis and offering a lucrative corridor for commercial developers who might otherwise contribute to the uncontrolled expansion of the suburbs. In this way, light rail lines are meant to expand their own range of service and thus increase their impact on traffic congestion over time.

Second, while it is true that the cars light rail takes off the road generally return on the order of months, numerous studies have shown a similar timeframe for expansions and additions to highway infrastructure. The Texas Transportation Institute is frequently cited by light rail opponents for its findings that congestion is just as bad in cities with light rail than in cities without it, but what the Institute itself chooses to emphasize is their finding that construction of new roads and lanes, when pursued unilaterally, is even more ineffective for reducing congestion in the long run. "Traditionally, transportation agencies have responded to congestion by trying to add more space to the road system. However, our
analysis of the TTI data shows this has proven to be an ineffective strategy. TTI's data show that places that have built the most roads haven't had much success in slowing growth in congestion...In part road building is ineffective because adding capacity to highways actually generates additional travel, as people take additional car trips and new development creates even more demand." All U.S. cities which introduce light rail do so because to some extent they are suffering from congestion and anticipate in increase in transportation demand. Thus, it should not be surprising that there is a high frequency of induced travel--trips which are taken because of reduced congestion and which subsequently raise congestion to its previous level. The same phenomenon occurs when roadways are expanded.

If neither expansions to roadways nor construction of light rail lead to immediate congestion relief, then how can their relative benefits be measured? Clearly, the observation that congestion is not significantly decreased in either case does not mean that the public is not gaining from the addition: people will be making trips they would otherwise have felt forced to do without because of congestion. How can we measure the benefits to well-being of infrastructural modifications if not by direct congestion figures? The Texas Transportation Institute promotes the use of a statistic called the Congestion Burden Index (CBI). This index incorporates the availability of public transit options into the TTI's standard rush hour congestion index (TRI). This adjustment makes the difference between San Fransisco's being ranked 2nd or 29th worst in the nation. It seems to make sense, because in cases where congestion after an infrastructural modification remains constant, those individuals who have the opportunity to ride LRT do not suffer from congestion, while those who drive on additional lanes or roads do.

Finally, LRT is favored by environmentalists not only because it reduces sprawl but also because it avoids contributing to air pollution along the line. (The Hiawatha cars will be electric.) A common criticism is that since the people who will ride instead of drive will be replaced by induced travelers, air pollution will not be reduced by LRT. Two answers are available--first, LRT obviously does avoid an increase in air pollution commeasurate with the increase that would have come from extra roads. Second, the Hiawatha line is planned to be only the first of many light rail lines in and leading out from the Twin Cities area. If the long term vision plays out successfully, a point will eventually be reached where we do see a permanent reduction in road congestion, which equates to a reduction in the rate of increased air pollution. This will come, in theory, as a result of "smart growth" policies which expand transit corridors in a centralized fashion that cannot be equaled by road construction alone.

In summary:

* What critics who claim LRT will not reduce traffic congestion never mention is that new and expanded roads also fail in the same way.
* The aim of the Hiawatha line is to improve conditions for the short and long terms along a particular traffic corridor, not to change transit habits over the entire metro area.
* Even when induced travel is equally quick to fill vacated thoroughfares resulting from road expansion or from LRT, the availability of light rail as a transit option reduces the stress and delays from congestion facing the average traveller.
* LRT aims to reduce urban and suburban sprawl and thereby to limit the demand for traffic in the long term, leading to a better natural and social environment.