Fairfax County police have rated the intersection of Arlington Boulevard and Gallows Road -- the scene of 66 traffic accidents last year -- as the most dangerous crossroads in the county for the second consecutive year.

Police blame traffic congestion and the massive road construction project at the intersection for the high number of accidents. The construction has disrupted traffic for almost two years.

"You really have to do some thinking when you get there because there're so many signs, so many cars and so many new office buildings," said police spokeswoman Connie Curran. "It's definitely, by far, the most dangerous intersection."

But the road construction that helped put the intersection on the "51 worst intersections" list for two years may knock the crossroads off next year's listing, police said.

"Within 60 days there really won't be an intersection," said Capt. Luther Nossett, who commands the police substation in Mason District where the intersection is located "As a matter of fact, I can't wait."

The accident-prone intersection has been under heavy reconstruction to separate the two roads by routing both the eastbound and westbound lanes of Rte. 50 beneath Gallows Road.

The 66 accidents at Arlington Boulevard (Rte. 50) and Gallows Road left 29 persons injured in 1985, police records show.

In 1984, police recorded 48 crashes and 17 injuries there, according to Curran. In 1983, before construction began, police listed 28 accidents and four injuries at the site.

Franconia and Loisdale roads near Springfield Mall ranked second on the list, which was released yesterday, with 55 accidents and 12 injuries.

No traffic fatalities occurred at either intersection, police said. Two fatalities were recorded during the year at the 51 intersections on the list.

Curran said accidents were included if they occurred within 100 feet of the intersection and involved more than $500 in property damage.