CLIFTON PARK — On the one-year anniversary of Joseph R. Riley’s death, family members and investigators still search for the driver of the vehicle who police say caused the accident that killed the former Clifton Park town supervisor and then fled the scene.

“We appeal to anyone that may have information to come forward,” Riley’s daughter, Tracey Collins, said Monday. “It won’t help to ease our grief about the tragedy, but it might provide some closure if we could understand how someone who was responsible could have driven away from such a horrible accident.”

Riley, who was 57, died instantly in a three-vehicle accident when his car was hit Aug. 24, 2007, at 4:18 p.m. as he drove eastbound along Interstate 90 between exits 3 and 4 in Albany.

Witnesses said the vehicle that left the scene, described as light in color, was traveling eastbound and struck the rear of a 2004 Hyundai. The Hyundai spun out, crossing lanes and striking the 2007 Toyota operated by Riley. Riley was ejected from his vehicle. The driver of the Hyundai that hit Riley’s car suffered minor injuries, officials said.

At the time of his death, Riley lived at 1914 5th Ave., Troy. A Democrat, he was Clifton Park supervisor from 1990 to 1991. During his tenure, Riley was credited with creating a townwide water system and instrumental in the drive to build the public safety building on Route 146. Riley was involved in establishing Clifton Park’s summer theater program and hosting its first July 4 celebration. Riley was also involved in the planning and building of Clifton Common, now a central hub of activity for families and site of the town’s ball fields, Shenendehowa Senior Citizens Center and CAPTAIN Youth and Family Services Inc.

A few years before his death, Riley moved to Troy where he was active in the Democratic Party and served on the board of directors for the Troy Boys and Girls Club.

Since last August, interviews with witnesses have failed to identify the driver of the light colored vehicle that left the scene of the accident. Police said there were hundreds of motorists delayed that day last year during rush hour traffic and the resulting congestion tied up the interstate for more than an hour.

“This case isn’t closed, and this anniversary is a chance for us to beat the bushes,” state police spokeswoman Trooper Maureen Tuffey said. “Someone may have seen a car leaving the scene in a panic and not realize that person was never apprehended.”

Tuffey said it’s also possible the suspect may have slipped up during the last 12 months and disclosed some information.

“Maybe the person was drinking and told someone,” Tuffey said. “What we’re trying to do now is tickle someone’s memory.”

Meanwhile, family members marked the anniversary with quiet time together remembering a man who had been an important part of their lives.

“People say time heals all, but every birthday, holiday and every regular day is hard,” Collins said. “It was a tragedy we still don’t understand.”

State police at Loudonville are asking anyone with information to call 783-3211.