The widening of U.S. Highway 17 in Mount Pleasant, in addition to slowing traffic, is being blamed for fewer people taking CARTA buses.

William Hamilton, an attorney and mass-transit advocate, told the board of the Charleston Area Regional Transportation Authority on Wednesday the problem these days for bus riders is safely getting to the bus stop on foot.

“The numbers held up until they tore up the sidewalks. Once the nightmare is over, it’s going to take a significant community effort to push ridership back up,” Hamilton said.

The problem is particularly bad for elderly riders, he said.

Numbers for CARTA riders in June released Wednesday supported what Hamilton said. They showed 1,748 people took the 401 East Cooper Connector in June of 2011 compared with 826 riders in June of this year. Hamilton said the bus has trouble running on time because of congestion caused by the road construction. The number of riders for June was down on the other two routes east of the Cooper, too, but not as much.

CARTA Executive Director Christine Wilkinson agreed with Hamilton’s assessment of the drop in East Cooper riders. “It’s construction. It’s a lot less utilized,” she said.

New sidewalks being built on frontage roads as part of the Charleston County Roadwise Johnnie Dodds Boulevard project should help increase CARTA riders when the project is finished at the end of the year, Hamilton said.

Overall, CARTA on Wednesday reported 399,342 passengers for June, which is nearly 4 percent more riders than June of last year. Revenue was up last month, too, to $322,000 compared with $303,000 for June of last year.

Voters approved a half-cent sales tax for transportation improvements, such as the $60 million boulevard-widening, the largest project in the Roadwise program. The boulevard project will improve about three miles of U.S. 17 from just north of the Arthur J. Ravenel Jr. Bridge to the south side of the I-526 interchange, including associated frontage roads and side streets. It is being widened from two to three lanes in both directions.

Frontage roads will be widened to provide one lane in each direction with 4-foot-wide, marked bicycle lanes and sidewalks.