Since Bay Area bridges implemented new tolls three weeks ago, 30 percent fewer people are using the carpool lane and the commute is faster than it was this time last year.

The traffic data were released Wednesday to the Metropolitan Transportation Commission, the first report since July 1, when a new $2.50 toll was charged on carpool drivers and congestion pricing was implemented on the Bay Bridge. Traffic officials say it is too early to pinpoint trends and they will continue to study the driving patterns to see if any changes to the tolls need to be made in the future.

The data showed there were about 12,000 fewer carpoolers on Bay Area bridges July 12-23 and 2,300 more full-fare drivers each day compared with the same period last year.

The most pronounced change was at the Bay Bridge - the busiest bridge in the region - which saw 6,199 fewer drivers roll through the toll plaza each day.

Drivers who use the Bay Bridge from 5 to 10 a.m. and 3 to 7 p.m. are now charged $6 on weekdays. The toll is $4 at all other times during the weekday.

Twice as fast

Data showed that traffic at the Bay Bridge during its busiest hours has moved twice as quickly as it did during the same period last year, a result of a drop in drivers and a shift in when they cross the span to avoid paying an extra $2.

"I think what you are seeing here is that we are having our cake and eating it, too," said Steve Heminger, executive director of the Metropolitan Transportation Commission, the regional planning and funding agency. "We're raising revenue and seeing decreased congestion."

It is difficult to identify the exact cause for the drop in carpool drivers with only one month's worth of data, said Rod McMillan, director of bridge oversight and operations.

The most likely explanation, he said, is that drivers who used to use the carpool lane without the requisite number of people in their car are less likely to cheat the system if they now have to pay a toll.

Before July 1, many drivers could slip through the carpool lane unnoticed. But now that they must have a FasTrak transponder, they are less anonymous.

When drivers don't have FasTrak, a photo is taken of their license plate and they are fined $25. Even with the pass, drivers are charged $2.50 and risk a $381 ticket if they don't have the requisite two passengers, McMillan said. Drivers may not use cash in the carpool lanes.

"For the occasional cheater, there is a lot more risk involved," McMillan said. "You are going to pay something where it was free before."

New commuting habits

Commuters may have also found other ways to get into the city.

Michael Corr, 34, said he used t0 casual carpool from the East Bay into the city but stopped after he had to start contributing a portion of the toll.

Now, he usually just drives himself.

"There was a wait (for a carpool) but you could tell yourself it was worth it because you weren't paying," he said. "It is disincentivizing now that I have to pay."

Others appear to have turned to BART, which marketed itself to carpoolers disappointed that they would no longer get a free ride.

Since July 12, roughly 1,500 more people have ridden BART into the city each day between 5 and 10 a.m. compared with the same period last year, said Jim Allison, a BART spokesman. The total number of people riding both to and from the city each day has increased by an average of 4,500, he said.

After the new toll went into effect, the transit agency gave many carpoolers free vouchers to ride BART.

Ticket vs. toll

While the commute-hour tolls have smoothed what is usually a notoriously difficult commute across the Bay Bridge, the number of cars on the road at 10 a.m., just after the toll drops by $2, has increased. In fact, many drivers pull to the side of the road, put their emergency lights on, then zoom ahead at 10:01 a.m., said Jagjit Dhillon, Bay Bridge toll captain.

That is against the law, said California Highway Patrol Sgt. Trent Cross. The CHP has no plans to regularly station officers near the toll plaza but could do so if stalling motorists continue to be a problem, he said.

"You know, paying the extra money is certainly cheaper than paying the fine or going to traffic school," he said.