Traffic is up this year at two toll bridges operated by the Burlington County Bridge Commission, where tolls have remained at $2 for 12 years.
Federal investigators said this month that they were examining toll increases on local bridges and on bridges and tunnels linking North Jersey and New York City following a request from U.S. Sen. Frank Lautenberg (D., N.J.).
The Government Accountability Office, the investigative arm of Congress, said it wanted to know how toll increases were determined and why.
Lautenberg wrote to the GAO in March, asking it to examine toll hikes, use of toll revenue, and "the transparency and accountability of the funding and management decisions" at interstate tolling authorities.
From 55.1 million vehicles in 2007, traffic on the four DRPA bridges is likely to decline to about 47.9 million vehicles this year, based on the first five months of the year.
Meanwhile, ridership is rising on the PATCO commuter rail line that links Philadelphia and South Jersey, on pace to have its best year since 1999. That is despite five hikes that have boosted PATCO fares by 88 percent since 1998.
PATCO, which is owned and operated by the DRPA, is on pace to carry 10.8 million passengers this year, up from 10.5 million last year and 8.9 million in 2003.
"We suspect that a variety of factors affect bridge traffic, and right now, we're facing a perfect storm of several," DRPA spokesman Tim Ireland said. "Gasoline prices remain high. Parking fees in Philadelphia remain high. The economy - particularly in Philadelphia and its western suburbs, where many New Jersey commuters traditionally have worked - remains flat.
"The Walt Whitman Bridge is under construction, and, of course, we increased tolls about one year ago."
Ireland said gas prices, highway congestion, and growing environmental consciousness are all likely contributing to the boost in PATCO ridership.
"Gas prices are probably the prime driver," he said. "Almost every big bump we've seen in PATCO ridership follows an increase in gas prices. One of the biggest jumps took place in the mid-1970s."
The Betsy Ross Bridge, the least-traveled of the four, is suffering the biggest loss of traffic this year, down about 9 percent from a year ago.
Part of the reason is likely its proximity to the less expensive Tacony-Palmyra Bridge, operated by the Burlington County commission. Tolls on that bridge have remained at $2 for 12 years.
Traffic on the Tacony-Palmyra has been rising, Last year, 9.8 million vehicles crossed the span, up from 9.4 million in 2010, and traffic is on pace this year to hit 10.3 million vehicles, based on the first five months of the year.
On the Burlington-Bristol Bridge, also operated by the Burlington County commission, where tolls have also remained at $2 for 12 years, traffic is up this year: Through the first five months of 2012, 1.77 million vehicles crossed the bridge, compared with 1.72 million last year.
Contact Paul Nussbaum at 215-854-4587 or firstname.lastname@example.org.