Charleston's peninsula is expected to add 25,000 residents in the next 15 years, but few believe there's room for that many more new cars.

That's why planners and preservationists are teaming up to figure out how best to move a growing population around downtown.

The Historic Charleston Foundation, the Charleston Area Regional Transportation Authority, the city's top planner and other experts will spend much of Tuesday discussing how the city's transportation options should and could shift over time.

They will detail their thoughts and findings at 7 p.m. in Charleston Music Hall, 37 John St. The event is free and open to the public, which will get a chance to participate toward the end.

Tim Keane, the city's director of Planning, Preservation & Sustainability, has said the peninsula, which now has about 35,000 residents, could grow to 60,000 by 2029.

The historic nature of much of downtown prevents any major road-widening projects, so walking, biking and public transit are expected to play growing roles. Last week, Keane told business leaders a key issue for downtown Charleston will be "carving out" space on existing streets to improve mass transit.

"We certainly feel the issue is not so much how to reduce congestion, but to figure out how you can drive less, and not have to rely on a car," he said. "This is a huge issue for the community."

He also said there needs to be more remote parking, so more people can park outside downtown and catch a shuttle or trolley to work - as some current employees do at the College of Charleston and Medical University of South Carolina.

Tom Bradford, director of Charleston Moves, recently spoke to Historic Charleston Foundation's annual awards gathering and said the future of the city's transportation could benefit by recalling how people got around the city in the past - long before the advent of the automobile.

"You'll find the streets were made for people," he said. "Later, we made them for people and cars."

Bradford said many people consider Charleston Moves as a bicycle advocacy group, "but we're really liveability advocates." Making more trips by foot or by bike offers health and environmental benefits as well as easing congestion, he added.

"Admittedly, we have work to do. Many are breezing through stop signs and stop lights," he said of cyclists. "We have to improve that."

For more information on Tuesday's event, visit historiccharleston.org.

David Slade contributed to this report. Reach Robert Behre at 937-5771.