Texas report shows folly of light rail
Does building freeways make congestion worse? Will light rail and commuter rail reduce congestion?
We can find answers to these questions in the Texas Transportation Institute's latest annual congestion survey,
which was released Tuesday.
Using highway data for 75 American cities from 1982 through 2001, the institute -- a part of Texas A&M
University's engineering program -- shows that congestion costs have more than quadrupled in the past two
decades. Congestion forces motorists to burn an extra 5 billion gallons of fuel each year and costs commuters in
major urban areas more than $1,200 per year each.
Some regions, such as Las Vegas and Orlando, have greatly expanded their freeway systems. The Texas
data show that new freeways lead to more freeway driving, but not more total driving. Instead, freeways
attract motorists away from other roads and streets. Since urban freeways are the safest roads we have, new
freeways both relieve congestion and improve traffic safety.
Other urban areas, such as Portland and San Francisco, have focused on rail transit rather than roads. This has
not been as successful in reducing congestion. Nine of the 10 urban areas with the fastest-growing congestion
are rail cities, with Portland and San Francisco tied for second.
There's a good reason why rails don't work. Portland's light-rail lines average just 20 miles per hour, so they
attract few people out of their cars. Since most rail riders are typically former bus riders, rails are ineffective at
The Texas Institute estimates that 14 new lane-miles of freeway per year would allow Portland to keep up with
traffic. Each mile of light rail costs four times as much to build and carries less than half as many people as a
freeway lane mile. If half of light-rail riders are former auto drivers, Portland would have to build 60 miles of
light rail each year, at 16 times the cost of 14 lane-miles of freeway, to obtain the same congestion relief.
Still, the Texas report shows that building more freeways isn't the only answer to congestion. The report
evaluates other options such as freeway ramp metering, traffic signal coordination and HOV (high-occupancy
Ramp metering and traffic signal coordination, says the report, have successfully reduced congestion at a low
cost. HOV lanes haven't worked as well, but many transportation experts suggest we turn HOV lanes into
high-occupancy/toll (HOT) lanes, which low-occupancy vehicles could use by paying an electronic toll. This
would give drivers a choice between taking the free lanes or paying a toll and getting home more quickly.
What about increasing residential densities, as Portland is doing? The Texas report shows that higher densities
are strongly correlated with more congestion. So-called "smart growth" does not solve congestion; it makes it
In short, rail transit won't reduce congestion, but transportation planners have other means to cost-effectively
reduce the time and fuel Portlanders waste in traffic.