Three fire departments in Bethesda have asked Montgomery County officials to add more units to emergency calls on the Capital Beltway because there have been numerous incidents in which fire and rescue personnel have been dispatched to the wrong section of roadway.

So far, county officials have declined the request from the Bethesda-Chevy Chase Rescue Squad, the Bethesda Fire Department and the Cabin John Volunteer Fire Department. The departments want an additional fire engine and ambulance to be dispatched to all motor vehicle accidents on the Beltway's outer loop between River Road and the American Legion Bridge.

Peter Morris, assistant chief at the B-CC Rescue Squad, said the problem arises in part from confusion on the part of motorists about exactly where on the Beltway an accident has taken place.

Morris said that local fire and rescue officials believe some of the mistakes in reporting accidents are attributable to a lack of landmarks along this section of highway, which begins just beyond the merge of Virginia-bound traffic on the Beltway and the Interstate 270 spur. The long entrance and exit ramps at River Road, including one that is more than half a mile long, add to the confusion, he said.

Data on how many erroneous dispatches have been made are not available, but Morris said there is enough anecdotal evidence to raise concerns. By adding an ambulance and a fire engine to the three vehicles that now respond, he said, the county would assure that a longer stretch of the Beltway is checked once an accident is reported.

"There have been times when accidents have been missed because they've fallen into what is, in effect, a black hole on the Beltway," Morris said. "We need to make sure that we do everything we can in order to make sure that we don't miss even one accident."

The three local departments made their requests to the county in a March 31 memo to Gordon A. Aoyagi, the county's fire administrator and chairman of the Fire and Rescue Commission.

Chiefs Lewis German, of the B-CC Rescue Squad, James Seavey, of the Cabin John Volunteer Fire Department, and Dennis Urban, of the Bethesda Fire Department, wrote that they were making the request to add an ambulance and fire engine to the dispatch assignments on the Beltway because "of the numerous instances in the past in which the calling party provides the incorrect location."

After an initial review, the commission's operations committee rejected the request earlier this month, even though its members agreed that the location of incidents on both the Beltway and Interstate 270 are frequently reported incorrectly. Instead, committee members asked Aoyagi to explore the possibility of improving signs or mile markers in the areas of these highways that are prone to confusion.

The Fire and Rescue Commission has the final say in how county dispatch assignments are drawn up.

Aoyagi said that following their initial review, commission members determined that the current assignments adequately address the problems raised by the chiefs. He said there was a concern that adding two units to the three that already handle Beltway calls could leave other emergency calls shorthanded. "There was a concern about how to balance resources," he said.

He also said that a review of emergency calls in the area did not turn up any incidents that point to a problem in the way emergency vehicles are dispatched. The lack of hard data, he said, makes it more difficult to quantify the problem.

But, he said, the request will be reviewed again by the Fire and Rescue Commission's operations committee. Aoyagi said he would also like to see if the county's Traffic Management Center, which uses video cameras to monitor traffic throughout the county, might be able to help fire and rescue officials better pinpoint the location of Beltway accidents.

"Given the technology we have in the county, this might be a way to address the issue," Aoyagi said.