Rising unemployment and gasoline prices below $4 a gallon are taking a toll on public transit ridership in Honolulu and nationally.

From July to September, bus and heavy-rail ridership nationwide fell nearly 8 percent and 4 percent respectively, according to the American Public Transit Association. In Honolulu, the number of riders on TheBus was down about 2 percent since July, according to the agency that operates the system.

The popularity of public transit increased in the summer and fall of 2008 when gasoline prices locally and nationally soared above $4 a gallon. At the time, the question was whether increased mass-transit ridership signaled a new era when a significant number of residents shift from driving alone to work to riding a bus or train.

Ridership declines suggest that may not be occurring .

Roger Morton, president and chief executive of Oahu Transit Services, which operates TheBus, said bus ridership dipped slightly in the last half of 2009.

Factors that could be contributing to lower bus ridership include a drop in gasoline prices, increased unemployment and a 25-cent fare increase on July 1 to $2.25. TheBus fares are scheduled to rise another 25 cents this July.

Morton said he's encouraged that ridership declines haven't been worse.

"Our ridership numbers are down a little bit, like in the 2 percent range or something, less than the national" figures, he said. "Most people who ride a bus --— 60 percent of our ridership — are people that are going to work. So obviously if there aren't as many people in Waikíkí working in hotels, if there aren't as many people visiting because arrivals are down, if we raise fares, I think all of those things would be contributing factors."

Overall, Honolulu has had relatively high bus ridership. In 2008, 5.6 percent of Hawai'i commuters used public transportation, while 66.8 percent drove to work alone, according to U.S. Census Bureau figures. Nationally, 4.9 percent of commuters used public transportation while 75.8 percent drove to work alone.

However, Honolulu's ridership has not kept pace with population increases.

Founded in 1971, TheBus experienced robust growth during the 1970s oil crunch. Ridership growth tapered off in the 1980s and peaked in 1994 with 77.3 million annual passengers, according to the Hawai'i Data Book.

Honolulu's planned rail line from East Kapolei to Ala Moana is expected to boost public transit use by about 1 percentage point by offering faster, more reliable service than buses.

On the Mainland, commuter rail lines have experienced ridership declines in recent months, according to the American Public Transit Association.

Among recently opened train systems, ridership on the Charlotte, N.C., light-rail system dipped 2.5 percent through September while light-rail ridership in Salt Lake City fell nearly 7 percent. Light rail in Charlotte and Phoenix are still outstripping initial forecasts.

Honolulu Transportation Director Wayne Yoshioka said city officials aren't concerned about declining public transit nationwide .

"We don't care what the Mainland is doing," he said. "The point is that we have extremely high transit ridership on a per-capita basis. We're worrying about what we're doing here, not what the Mainland is doing in terms of transit ridership."

Panos Prevedouros, a University of Hawai'i transportation engineering professor who is at the forefront of opposition to Honolulu's rail project, said recent declines in public transit ridership are part of a predictable pattern where ridership spikes following fuel price increases, only to fall back when prices decline.

"The ridership decline is significant (because) they have so many factors going for them with the energy prices and even the decrease in income due to unemployment, and apparently, they (commuters) don't stick" with public transit, Prevedouros said. "Time and again we notice in the oil crisis and all, there is a little uptick (in ridership), Congress rushes to support mass transit systems, and essentially the (ridership) bubble disappears ."