Later this month, friends will gather at St. Anthony's Catholic Church in Fairfax County for a memorial mass for Sharon Smith, 45, who was killed by a hit-and-run driver as she walked across South Jefferson Street at Leesburg Pike on Jan. 26. The driver whose vehicle struck her has not been found.

The Baileys Crossroads intersection where Smith was struck is in the most accident-plagued corridor in Fairfax County, an area where officials say road improvements have not kept up with residential and commercial growth.

Last Monday, two other women were struck by a car at the same intersection. Both were seriously injured and remain hospitalized. Police have decided not to charge the driver in the latest accident, saying it was not the driver's fault.

"That's a horrible area for both pedestrians and drivers," said Connie Curran of the Fairfax County Police Department. "We have some of the worst intersections, as far as number of accidents and seriousness, right there."

"A lot of times the biggest problem is the traffic signal time," said Eric Foster, a project planning engineer for the Faifax Office of Transportation. The signal lights give so much time to vehicles and so little to pedestrians that officials are considering erecting a pedestrian bridge in the area, he said.

Tremendous growth in Baileys Crossroads is causing traffic problems, said Supervisor Thomas M. Davis II, who represents the area. "We've got a lot of cars on the main thoroughfare, especially on Saturdays, when the retail outlets draw traffic onto Rte. 7 Leesburg Pike ," said. Davis, who has named a task force of residents to study and make recommendations on traffic problems. "We've also got 10,000 residents within a square mile" of where the recent accidents occurred."

Two Baileys Crossroads intersections were near the top of a police list of most dangerous intersections in 1983, the latest year for which complete figures are available. Arlington Boulevard and Patrick Henry Drive was first, with 55 accidents, while Arlington Boulevard and Annandale Road was fourth, with 35 accidents. Both are within two miles of the site of the two recent accidents.

At Patrick Henry Drive, there are "too many uncontrolled movements now," said Foster. "We've tried stop signs and no-turn signs, but there's a high rate of traffic violations there."

A study there by a consulting firm showed 207 violations between 7:30 and 8:30 a.m. one weekday morning, Foster said.

The county has traffic plans designed to eliminate some problems in the area, but construction will take at least a year. "The plans call for some pretty get-tough stuff, changes that will prohibit some moves" by drivers, Foster said.

"We're currently completing an improvement plan . . . putting in medians to prohibit turns onto the main road from service lanes . . . , " said Philip Schirmer, chief of the county's road design branch. "The changes would mean service lanes would only serve shopping centers."

Only in 1981, as the Virginia Department of Highways and Transportation suffered a severe revenue shortage, did Fairfax County begin designing and building roads with county funds. "Because of the number of accidents and the severity of them, we felt we had to get in the road business," Schirmer said.