Costly Benefits?

Transportation consultants hired by the city's Public Works department say that the benefits of widening Lamar Bridge to six lanes far exceed costs. Their cost/benefits analysis assumes a 48% increase in traffic on the bridge by 2020, and predicts that reducing projected peak-hour delays would save motorists $7 million in time annually, and another $500,000 in fuel. With costs for construction and interest on bond payments estimated at $944,900 per year, the consultants figure that the benefits outweighed the costs by 8.4 to one.

However, neighborhood activists say that the benefits will accrue mainly to motorists commuting from subdivisions to the south and west by way of MoPac, US 290, and Bee Caves Road, and will encourage more development over the Edwards Aquifer and its Hill Country contributing zone. Meanwhile, inner city neighborhoods will bear the brunt of the costs through higher taxes and more traffic, noise and air pollution.

Some traffic planners, in fact, have begun to question traditional cost/benefit analyses that take into account only benefits to motorists, without giving serious consideration to the costs of environmental damage and deterioration of inner-city quality of life. Charles L. Wright, author of Fast Wheels, Slow Traffic, calls the value of motorist time saved in most cost/benefit studies "numerical silly putty."

"The mathematical models used to generate this figure typically include savings of a few seconds," Wright says. "When multiplied by millions of users and a given wage rate, these seconds produce large monetary benefits and an economic justification for almost anything." According to Todd Litman, Director of the Victoria Transport Policy Institute in Victoria, British Columbia, "Most roadway improvement analyses overstate traffic congestion reduction benefits and understate costs by ignoring the impacts of generated traffic. External costs of generated traffic (increased parking demand, congestion on other roads, air pollution, energy consumption, urban sprawl, etc.) should be a cost of congestion reduction projects." Litman's own analysis shows that American taxpayers subsidize motorists up to 61cents a mile during peak-hour driving for these costs, which are routinely ignored by traditional traffic planning. That adds up to $13.42 for the average 22-mile roundtrip peak-hour suburban commute.

Public Works claims that expanding Lamar to six lanes will save 1,724 pounds of air-polluting exhaust emissions per year because of reduced stop-and-start driving. However, this assumes that an additional 22,000 motorists per day will use Lamar Bridge by 2020 even if it is not widened. Environmentalists point out that the additional 22,000 cars will add significantly to the city's air pollution whether they move over the bridge a few seconds faster or not.

According to a 1995 report by the city's Environmental and Conservation Services Dept., "Increasing traffic flow encourages more use of roadways, and can create net increase in traffic volume and air pollution." The report concludes that Austin's main hope for slowing air pollution is not road widening, but increasing transit and bicycle use, and controlling urban sprawl. -- N.E.