By December, passengers on AC Transit line 51 will see a significant improvement in service after Berkeley City Council unanimously greenlighted a new plan aiming to make the line more reliable and sustainable.

The project, approved April 1, hopes to ameliorate traffic flow — thus reducing travel times — as well as improve air quality and enhance ADA accessibility and public safety along the corridor. The line, which operates within the cities of Berkeley, Oakland and Alameda, has a weekday ridership of 19,000 passengers, making it the most widely used route in the AC Transit system.

“We are going to try and fix the reliability and make bus travel time a little quicker,” said Robert Del Rosario, director of service development for AC Transit. “We are hoping more people will be able to take the bus and get out of their cars.”

Main renovations include  bus stop relocations and improvements, minor lane striping changes and traffic signal upgrades. To boost flow, traffic signals will give buses an early or extended green light when approaching an intersection or provide buses with their own signal phase to get a head start in traffic, among other changes.

According to an AC Transit Line 51 Service and Reliability Report from December 2008, traffic signal operations accounted for 80 percent of overall delay on the route. Bus bunching, late vehicle arrivals and overcrowded buses have been pinpointed as the main nuisances for users.

“You can call and you can check on Next Bus and it will say five minutes, and it usually ends up being more like 20,” said Sara Dennis-Keep, a UC Berkeley freshman and bus rider.

The project is funded by a federal grant that allocated $10.5 million to AC Transit for the improvement of the corridor, of which roughly $3 million will be used for work in Berkeley on the 51B line. Oakland and Alameda are serviced by the 51A.

During the approval process, many items were removed due to concerns from community members. These elements included a proposed peak-hour bus-only lane down University Avenue and the installation of two traffic signals: one in Elmwood and one on the intersection of Bancroft Way and College Avenue.

“University Avenue merchants have been very active, because they were going to take all our morning and evening parking,” said Ellen Lasher, vice president of the University Avenue Association and business owner, adding that she is nonetheless happy with AC Transit’s work with merchants.

Farid Javandel, the city’s transportation division manager, said plans are almost finalized and that some more-controversial elements are now officially under consideration for approval by city engineers.

With work scheduled to begin in June, the plan is still undergoing final approval by the city of Oakland and has already been given the go-ahead by the city of Alameda, according to Javandel.