Yesterday’s Philadelphia Inquirer included an interesting piece on the NJ Turnpike Authority’s planned widening of the NJ Turnpike, which would add up to three lanes in each direction between exits 6 and 9 and cost about $2 billion. The article quoted officials from a metropolitan planning organization and a state-funded research center who question the effectiveness of adding general purpose lanes as a means to fix congestion:

Highway engineers have long dealt with the phenomenon of “induced demand,” the tendency for new lanes to attract new drivers. Human nature and traffic science make it inevitable, transportation experts say. […]

“When you make those kinds of improvements, capacity gets eaten up very quickly. About 80 percent of the new capacity gets used up right away,” said Donald Shanis, deputy executive director of the Delaware Valley Regional Planning Commission. “Any time you make a trip easier, you encourage more auto trips.”

Robert Noland, professor and director of the Voorhees Transportation Center at Rutgers University, said his research had shown that “if you add more capacity, it’s likely you’ll increase the number of cars.” […]

A more effective way to reduce congestion, Noland said, is to increase tolls at peak travel times.

The Turnpike Authority was an early pioneer when it came to congestion pricing — in 2000 it became one of the first transportation agencies in the region to charge drivers higher tolls during peak periods. Last month, the authority board voted to grant deeper off-peak discounts to seniors, truckers, and drivers of fuel-efficient and low-emissions vehicles.

Ironically, however, the authority gave short shrift to studying congestion pricing or other “demand management” strategies in its environmental reviews of both the Turnpike and Garden State Parkway widening projects, opting to simply lay more pavement (see, for example, “Contradictions and Non-Answers Part 2,” July ’08; MTR # 552).