Officials of the local American Automobile Association said yesterday that there have been five accidents on the Cabin John Bridge since reconstruction and resurfacing began three weeks ago. There may be "a 16-month-long headache [ahead] for motorists," officials said.

The AAA said it was so concerned about the traffic hazards there that it would mail free alternative-route maps showing how to bypass that part of the Capital Beltway to anyone who requested them.

"They're our aspirin remedy," AAA-Potomac staff director Tom Crosby said yesterday. "We're showing people ways to avoid the bridge, to try to cut down on the delays and jams" that have already caused backups of more than two miles in recent weeks.

AAA is also inaugurating a 24-hour hotline (222-6200) to relay the construction crews' reports on special delays.

The AAA suggestions are intended for use primarily between 9 a.m. and 3 p.m.; during rush hours, all lanes on the bridge are supposed to be open.

Since work began on the bridge Aug. 15, closing one lane in each direction at off-peak hours, "there have been at least five accidents, all of them rear-enders," Crosby said.

"They occur because people approach the bridge at high speeds, and the traffic is compressed from four lanes to two. . . . The speed limit there is 45. The highway department has 70 warning signs posted, some as far as five miles away, but people still come up doing 65."

And, Crosby warned, things are apt to get worse: "There will be more people now that vacations are over . . . and in winter, visibility is often affected by fog or snow." At times, four lanes of traffic may have to merge into one, and concrete barricades may frighten some drivers into thinking lanes are too narrow.

"We're telling motorists during the day, avoid the bridge if you can," Crosby said. "If you have to use that part of the Beltway, slow down. It's a high-danger zone."

More than 129,000 vehicles cross the Cabin John Bridge every day, according to official estimates. Under the best of conditions, it is a notorious trouble spot, and has been the scene of several accidents that have virtually locked up Beltway traffic for hours at a time.

The $14.3 million facelift of the bridge (officially, the American Legion Memorial Bridge) calls for a complete redecking of the pothole-plagued deck over the Potomac River and the joining of the twin spans into a single bridge.

Construction workers have about three months to sink moorings beneath the open center of the bridge before winter high-water levels impede them. Until Dec. 1, one lane on both the inner and outer loops will be closed between 9 a.m. and 3 p.m.

After Dec. 1, construction workers will close those lanes again between 8 p.m. and 6 a.m.: Occasionally during the night construction, as many as two lanes in each direction may be blocked.

The free alternate-route maps will be returned to area residents who send a stamped, self-addressed envelope to AAA-Potomac, 8111 Gatehouse Road, Falls Church 222047.

There are several options in each direction, Crosby said. Maryland-bound traffic from Northern Virginia, for example, might be diverted across Chain Bridge, Canal Road and Nebraska Avenue in Northwest Washington to River Road or Wisconsin Avenue and back onto the Beltway.

Southbound drivers might take Connecticut Avenue to Rock Creek Park off the Calvert Street ramp and use Virginia Avenue to cross Theodore Roosevelt Bridge into Virginia.

Although all these roads are heavily traveled, midday use is light, according to Crosby.