Transit and bicycle advocates supported a revised proposal Tuesday for a walkway without switchbacks on the Camden end of the Ben Franklin Bridge.

The cost estimate of the no-switchback option has been reduced to $2.9 million, engineers said at a public session Tuesday evening at the Camden headquarters of the Delaware River Port Authority, which owns the bridge and will build the ramp. The estimate had been $3.7 million.

Two other ramp options, one with three switchbacks (estimated cost $2.8 million) and one with a single switchback ($4.3 million), are also under consideration by DRPA planners.

All three would allow people in wheelchairs, as well as cyclists and walkers, to use the walkway on the south side of the 1.5-mile-long bridge. That walkway now ends in a staircase with 39 steps. On the Philadelphia end, the walkway descends gently without stairs.

John Boyle of the Bicycle Coalition of Greater Philadelphia and Matthew Norris of the Tri-State Transportation Campaign said a continuous ramp that follows the slope of the bridge would be easiest to use and would deposit travelers at Fifth Street in Camden, where it would be easy to connect to existing streets and planned bike paths.

David Simon, chairman of the DRPA board, said he was concerned that a continuous ramp could be dangerous because cyclists could go down it too fast.

The slope of the ramp on the Camden side in all of the options is designed to be 5 percent, the maximum permitted under the Americans With Disabilities Act and slightly steeper than the 4 percent slope on the Philadelphia side.

Project manager Dan Cosgrove said the DRPA hoped to select a preferred option in a few months and a final design by fall. The ramp is to be built next year.

The DRPA board removed plans for the ramp from its budget in 2011 in a cost-cutting move, but the agency restored the ramp after a concerted push by the bicycle coalition was joined by area business and political leaders.

"We're totally pleased with the design options and the progress they're making," said Boyle, the bicycle coalition's research director. "It's looking really good for the continuous ramp."

Until 1950, the bridge had a sidewalk that followed the slope of the bridge to the ground in Camden. It was replaced with the stairway during a road-widening project.