Trucks used to barricade roads leading to the Capitol over the weekend as part of an experimental security measure will continue to block the routes during nonworking hours for at least the next 30 days, a spokesman for the U.S. Capitol Police said yesterday.

Lt. Stephen Ring said the increased security was not in response to any specific threat, nor is it a permanent measure.

"These measures have been contemplated for quite a while, and we're just testing them out to see how effective they are," Ring said. "Other measures will be explored to enhance security without detracting from the overall appearance of the building."

Ring said the dump trucks, garbage trucks and other vehicles that began blocking seven access routes to the Capitol on Friday will continue to barricade the roadways during nonbusiness hours.

During working hours, he said, the barricades are not needed because access is limited by heavy traffic in and out of the Capitol and by numerous vehicles parked along the shoulders of the various driveways.

Trucks are parked at the Northeast, Southeast, Northwest, Southwest, Congressional, South Capitol Street and Maryland Avenue entrances to the Capitol grounds.

The remaining driveway, off East Capitol Street, was blocked with concrete barriers earlier this year as part of an effort to tighten security after the November 1983 explosion of a bomb outside the Senate chamber.