Hence, those drivers produce nearly the same amount as pollution since their cars will still have cold starts and engine cool down periods during those trips. Most of the nation's recent improvement in air quality can be attributed to improved auto emission technology, not because of light rail development. Expert after expert is debunking the myth that light rail is a panacea for urban traffic problems. Myth Number One is that light rail reduces traffic congestion. In fact, between 1986 and 1995 average daily trips on a main Portland freeway increased by 38 percent despite a parallel rail line.
Rail also does very little to improve air quality.
Light rail is not a cost-effective alternative to roadway construction. Such claims are based on the assertion that light rail offers greater commuter capacity than other transit alternatives, including buses. However, US Census data in 1990 showed that only 2,500 daily commuters used Portland's Eastside's light rail system that has a capacity of over 40,000. Light rail systems are extremely expensive. In addition, even light rail systems in large metropolitan areas often require additional operating subsidies.