On this day in 1995, to the likely dismay of Washington, D.C.-bound road trippers hoping for a glimpse of the presidential residence through their car windows, President Bill Clinton permanently closes the two-block stretch of Pennsylvania Avenue in front of the White House to all non-pedestrian traffic as a security measure.

The road’s closure had long been a desire of the Secret Service, who saw it as necessary in order to guard against the risk of a possible car- or truck-bomb attack. President Clinton, like other residents of the White House before him, had been reluctant to accede to the request, but finally bowed to the recommendations of a panel of security experts including representatives of the Secret Service. The panel had begun a security study of the White House in the fall of 1994, after a drunken pilot crashed his light plane onto the South Lawn in September. That October, a man fired a semiautomatic rifle at the White House from Pennsylvania Avenue; a passing tourist then tackled him.

While a vehicle-free Pennsylvania Avenue would not have prevented either of these incidents, attacks at the World Trade Center in 1993 and in Oklahoma City in April 1995 had highlighted the potential threat of a truck bomb. Other options–including stopping traffic at checkpoints at either end of the compound or limiting traffic to cars and small trucks–were ultimately rejected as impractical, and likely to create an even more unwelcoming atmosphere than closing the road entirely. As officials in favor of closure pointed out, the areas near Buckingham Palace and 10 Downing Street (the home of Britain’s prime minister) had long been closed to vehicular traffic for security reasons.

President Clinton announced the closing in his weekly radio address, calling it “a responsible security step necessary to preserve our freedom, not part of a long-term restriction of our freedom.” Before dawn on the following day, the authorities had erected concrete barriers at each end of the two-block stretch, a road that for almost two centuries had been–according to an article published in The New York Times on May 21–“the route of inaugural parades, protest marches and an untold number of bus tours.”