A bunch of "robberies-by-kidnaping" that D.C. police attribute in part to the season's warmer weather has hit the city, leaving motorists stopped at traffic lights with their windows open among the most vulnerable.

In the last two days, police reported, at least three persons -- a bookkeeper, a delivery truck driver and a department store vice president -- were abducted at gunpoint in their own vehicles, held briefly and then robbed. Other such abductions have occurred earlier this spring.

Late Tuesday, night, Philip Weinstein, a vice president of Woodward & Lothrop department store, and a friend, erry Brier, 52, of Wyllingboro, N.J., were accosted by two armed men in a parking lot at 10th and G streets NW. Weintein and Brier were forced into Brier's car and ordered to drive away.

The assailants, who had already struck Weinstein on the head with a pistol, directed Brier to a parking lot behind Dunbar High School near New Jersey Avenue and O Street NW, saying "Now we're going to take you to the ghetto," Weinstein told a reporter.

Once at the school, the assailants took cash and jewelry worth about $1,000 and the car keys from Weinstein and Brier and then ran away on foot.

Moments later, three others men approached the already victimized Weinstein and Brier and demanded money, but the victims escaped to a fire house across the street.

Weinstein was then transported to Georgetown University Hospital, where he was treated for severe cuts on the right side of his face and released.

In the second recent incident, James M. Posey, 56, a bookkeeper from Dumfries, Va., was stopped at a light at 11th Street and New York Avenue NW at 12:30 a.m. yesterday by a man with handgun who opened the driver's door, ordered Posey into the passenger seat and got behind the wheel.

A second man, who was carrying his knife, got into the back seat behind Posey.

The assailant drove Posey's car to the rear of a house on the 3100 block of Buena Vista Terrace SE, parked, the car and hit Posey in the head with his gun. The other robber then cut the wallet out of Posey's rear pants pocket and pushed him into the street. The assailants then drove away.

Police are still searching for Posey's 1969 AMC Rebel.

The third victim, Elijah Daniels, 27, told police he was delivering surgical supplies at the Washington Home, 3720 Upton St. NW at 1:30 p.m. Tuesday when two men, one with a handgun, yanked open the front doors of his truck, got in on either side of Daniels and drove off.

The assailants drove Daniels, who works for the Accredited Surgical Company, 8705 Colesville Rd. in Silver Spring, about seven blocks to Rodman Street NW when Daniels reached over one of the men, opened the door and jumped out of the moving vehicle.

Daniels was taken to Georgetown University Hospital, where he was listed in serious condition last night with head injuries.

A company spokesman said the robbers made off with about $500 worth of drugs. The truck was recovered near the Washington Home about midnight.

Investigations into the three incidents are continuing.