It's hotel checkout time on the kind of day cab drivers dream about--a rainy Thursday, with a builders' convention in town.

As Joseph Bradley pulls his hack into the tree-lined driveway of the Sheraton Washington Hotel on Woodley Road NW and looks for passengers, he recalls a time when the conventioneers would have been off limits to him.

Bradley, 54, started hacking the District streets 31 years ago, when cab companies were segregated and only Yellow Cab served the major hotels.

Although segregation once restricted Bradley to driving for small companies on the city's outskirts, he speaks almost nostalgically of an era when cab drivers were both trusted and revered in the community.

"People would put tiny infants in your front seat and say, 'Take my child home.' Men would cash their paychecks, give me the money and say, 'Take this home to my wife.' These days, even if someone gave me the money, I'd be afraid of being robbed along the way."

The city government apparently is also concerned about the image of its "unofficial ambassadors": It has planned a reception for Sunday at the Washington Convention Center to recognize the cab drivers' "vital role in promoting goodwill and tourism in the capital city."

Bradley, a graying, soft-spoken man who smarts under accusations that today's cab drivers are neither courteous nor trustworthy, hopes to use the occasion to make a pitch for more hack inspectors and better taxicab regulation. He believes younger, less conscientious drivers have corrupted an industry that in earlier times was known as the nation's finest.

Yet, he admits it isn't easy to adhere to his stringent cab driver code of ethics. Crime has gotten so bad, he said, he now thinks twice about whom he takes into his cab.

"You used to be able to go anywhere in the city, day or night, and you didn't worry," Bradley said of Washington in the early l950s. Back then, "temporary" government buildings dotted Southwest, streetcars crisscrossed the city's main thoroughfares and Northern Virginia was mainly "a swamp."

Georgetown, where Bradley lived until l952, was a "slum" of old homes with outdoor plumbing. He later moved to Northeast, driving as long as l8 hours a day to support his wife and five children.

He likes what he sees along today's streets. The sparkling new office buildings and the convention center traffic are the signs of a city suddenly proud of itself and its central role in the nation, he said.

But the changes the District has seen during the past decade have not entirely benefited cab drivers.

Integration in the late l960s dismantled the race barriers that once put all-white companies, including Yellow, Diamond and Liberty, off-limits to black drivers. But the past decade has brought rising crime rates, Metrorail and, most recently, competition from immigrant taxi drivers.

Bradley said a shortage of supervision four hack inspectors supervise the city's 8,500 cabs has caused drivers' performance to slip and with it their once glowing reputations.

"It's just not the same anymore. Washington used to have the best cab service in the country. Now people just don't care about the job anymore, and they're giving all of us a bad name," he said.

Many drivers overcharge, turn down fares and refuse to travel to "unsafe" areas, knowing they can do so with impunity, he said.

Donald Anderson, supervisor of the District's 0ffice of Public Vehicles, said he receives about 25 formal complaints a week about cab drivers. One driver allegedly charged $80 for a trip from National Airport to a downtown hotel, according to hack inspector Vincent Cerverizzo.

"A lot of these guys will just make excuses," Bradley said. "They know it's illegal to turn down a fare, but they say things like, 'I don't know how to get to that address.' That's nonsense. If you're a hack, you're supposed to know." Hacking is practically a family business for Bradley. Two of his brothers drive cabs, as does his 23-year-old son. It's a job for "the independent type," he said, and it is perhaps this very independence that has prevented hacks from organizing effectively.

"A lot of us would like to break up Zone 1 the central fare zone bounded by 22nd Street NW, Florida Avenue NE, 2nd Avenue SE and Maine Avenue SW . We don't really make any money on those $1.70 fares. But every time they have a hearing, so many different cab drivers' associations show up with their different ideas, they end up not giving us anything."

Associations in the city include the Taxi Industry Group, the Fraternal Order of Taxi Drivers and Taxi Owners, the Washington, D.C., Taxicab Association and the Professional Cab Drivers' Association, of which Bradley is president.

There have been some successes, though. In l978, after cab driver Timothy R. Young was slain in his cab, Bradley organized a 300-cab funeral procession that traveled down 14th Street NW past the District Building.

The procession, and subsequent meetings with then-Police Chief Burtell M. Jefferson, led to the installation of citizen band radios in seven police cars and about 350 cabs.

The late President John F. Kennedy and his brother Robert Kennedy rode with Bradley as U.S. senators. "John Kennedy was a friendly fellow," Bradley said. "Robert was a lot more quiet. I remember the first time I met him, I asked, 'Hey, (are) you Robert Kennedy?' And he just mussed up his hair and said, 'Why, do I look like him?' "

Bradley said Alabama Gov. George Wallace rode in his cab shortly before the l972 assassination attempt on him.

Bradley said he is pleased with Mayor Marion Barry's suggestion that hacks act as unofficial ambassadors in a city where the second biggest industry is tourism.

"I'm always willing to tell someone that there's the Washington Monument, that it's 550 feet high and that it has 898 steps and that the elevator will get you up to the top in 62 seconds and that you used to be able to walk up to the top until it got crowded and they had to make people ride the elevator."

"It's just part of my job," he said. "Some of the younger drivers complain that the public expects too much of them. But I say you have a responsibility to the public. We need that kind of attitude again. We need cab drivers that the people can trust."