Even children of permissive parents know better than to accept rides from total strangers. Yet adults do it all the time--which is one reason why it makes sense for taxis to be one of the most heavily regulated businesses in America. The flip-side of consumer protection, however, is that cab operators have long been able to guarantee themselves profits by pulling regulatory strings at City Hall.

In San Francisco, for example, cab companies have been able to keep the number of medallions, or licenses, so low as to pretty much limit cab service in that city to the profitable runs between the major downtown hotels and the airports. Passengers who want to go somewhere else are usually out of luck.

But some jurisdictions are starting to change the rules in favor of the riding public. In Washington, D.C., Mayor Adrian Fenty recently announced that he would put an end to the city's bizarre and long- entrenched zone system, in which riders are charged a fixed amount for traveling within a geographical zone or crossing into the next one-- regardless of whether they traveled miles across town or rode for only a few blocks.

What's worse, because zone lines were unclear and subject to much dispute, passengers (especially tourists) were commonly ripped off by drivers who could make a couple of extra bucks by pretending that a ride of two zones had crossed into a third. Also, without meters providing revenue documentation, drivers found it easy to mask their true earnings when it came time to pay the city tax department its share.

Under Fenty's new system, all cabs will come equipped with meters that will accurately compute the mileage of a given ride and compensate drivers for time stuck in traffic. People who ride for 10 blocks will be charged less than those who ride two miles--a novel situation in Washington.

The fact that drivers are unhappy about this situation was amply demonstrated by their marginally successful 24-hour strike on Halloween. "The mayor did his thing again," complained William Wright, president of the taxi operators group that organized the strike. "He doesn't care about the cabdrivers; he's catering to the public."

Catering to the public may, in fact, be a wrong-headed idea, argues Marc Fisher, a Washington Post columnist and fan of the zone systems. Fisher believes meters will attract commercial fleets that will drive down business for the city's mostly independent operators.

"Those cab companies--and this is no secret, they will happily tell you this straight out--will seek to have the city place some limits on the number of cabs in town," Fisher says. "They will argue that there are too many taxis here, and by the standards of the fleets, there are."

In other words, in Fisher's view, what looks like a pro-consumer move right now may ultimately backfire. But only because the cab companies are confident that they will, once again, be able to bend the rules in their own favor.