This town has changed irreversibly since Sept. 11, 2001. Most of us probably are unaware of the extent of the security measures implemented since that day. There may be, for example, more security cameras mounted in public spaces here than in any other 66-square-mile area in the country. Who really knows?

But while some clandestine intelligence gathering is largely hidden from you and me, other not-so-subtle security activities are orchestrated with the opposite effect.

The vice president's compound on Massachusetts Avenue is the scene of one of the most irritating precautions of the post-9/11 era. Each time Mr. Cheney is scheduled to be at the White House for a morning meeting, a motorcycle escort roars out of the Observatory Circle encampment, shattering the otherwise tranquil morning. The volume of these machines is adjusted to rattle residents, bystanders and wildlife as far away as Glover Park, mirroring the administration's "shock and awe" strategy.

The intended effect may be to frighten (or deafen?) any subversive in the area. Anyone walking down the street or waiting for a bus might develop a nervous disorder and qualify for disability after a few episodes of this ritual -- a unique strategy for crippling a local fundamentalist cell. If I were a conspiracy theorist, I might conclude that another aim of this madness is to terrorize the otherwise peaceful worship taking place at the Islamic center at 2500 Massachusetts Ave.

The first bikers exit the gated grounds waving and gesticulating wildly for all traffic -- coming, going or crossing Massachusetts Avenue -- to cease and desist. The scowl and violent gestures of the first rider propel drivers to obey more out of fear than respect. The underlying message is that if you don't yield fully and right away, you will get not only a traffic ticket but also a drill sergeant's tongue-lashing. This stream of cannon-fired motorcycles stops traffic in its tracks and carves a path for the VIP to follow, treating all motorists as potential car bombers.

Moments later the police squad cars and the telltale black Chevy Suburban with tinted windows emerges, carrying who-knows-who. They may take Rock Creek Parkway or 23rd Street or they may sneak through Woodley Park to Connecticut Avenue on their way to the White House -- all designed to keep John Q. Terrorist guessing.

On Rock Creek Parkway, a dismounted motorcycle cop stands ready with his two-way radio and policeman's whistle. When he gets the signal he steps out into southbound traffic, and commuters slam their brakes so that operation "rolling thunder" can proceed to 1600 Pennsylvania Ave. unmolested.

While waiting in this pre-authorized traffic jam, I have often asked myself how many times it is all a decoy attempting to sucker an Embassy Row anarchist into tipping his hand and exposing his massive underground network of neighborhood subversives. Having feigned his trip downtown, Vice President Cheney could then catch a cab to work and bum a ride home, maybe with someone from the Old Executive Office Building. A perfect cover.

Alvin Hutchinson is a librarian who lives and works in the District and has been an intra-city commuter for more than 10 years. He considers the occasional VIP security entourage an inconvenience but at the same time an airtight alibi for being late to work. He enjoys gardening and basketball and is a volunteer computer literacy instructor.

Alvin Hutchinson is irritated -- and amused -- by the high-decibel, traffic-halting security measures he witnesses on mornings Dick Cheney leaves the vice presidential compound off Massachusetts Avenue.