SUMMERVILLE — A plan to get a few hundred cars off congested I-26 will be unveiled Monday.

The Charleston Area Regional Transportation Authority wants to start an express bus service between Summerville and Charleston. The idea builds on the success of the express route from North Charleston that started in January.

CARTA has been getting feedback from commuters through bus drivers and the CARTA Web site that shows a strong demand for a bus from Summerville, CARTA Executive Director Howard Chapman said.

"We feel there is substantial interest," Chapman said.

Every day, about 250 people park their cars in the Super Kmart parking lot in North Charleston to ride the express bus to downtown Charleston, Chapman said. Many of those commuters drive from Summerville, he said. More would take a bus downtown if it started in Summerville, he said.

The Summerville route would start in the Heritage shopping center at the Berlin Myers Parkway and East 5th North Street, he said.

A bus from Summerville also could help get government money for a train from Summerville, which is what a lot of commuters have been asking for, he said.

"This is really just the first step in looking at the viability of commuter rail," Chapman said. "This could show that people will leave their automobiles and use public transportation."

Money also is the challenge for starting a bus from Summerville. CARTA would need up to a half-million dollars from Dorchester County, Chapman said.

Dorchester County Council would consider money for a bus only if a large number of voters supported the idea, Council Chairman Larry Hargett said.

"This will be first exposure to the idea, too," Hargett said of Monday's hearing. "We'll hear what they have to say."

Overall, 18,000 riders a month use the two CARTA express buses that started in January, Chapman said. That would be about 900 people if the same commuters use the bus each day. The buses run on weekdays during the morning and afternoon peak traffic hours.

One bus goes from the Super Kmart on Rivers Avenue to James Island. The other goes from the Kmart on Johnnie Dodds Boulevard in Mount Pleasant to Citadel Mall in West Ashley. A one-way ticket costs $2, and a monthly pass costs $64. A price for a Summerville bus ticket has not been set.