Mayor Adrian M. Fenty announced today that D. C. taxicabs must switch to time-and-distance meters by April 1, abandoning a decades-old and controversial system of zoned fares.

Fenty (D) and D.C. Taxicab Commission Chairman Leon Swain Jr. said that the price of a taxi ride would start with a $4 base charge, plus 25 cents for every sixth of a mile after the first sixth of a mile traveled.

That means a ride of two miles, without significant traffic or other factors, would cost a minimum of $6.75, compared to a minimum fare of $6.50 using the current system.

But for every minute stopped in traffic, or traveled at a rate of speed slower than 10 mph, the rider will be charged an additional 25 cents -- charges that do not exist in the zone system.

As in other cities, there will be myriad possible surcharges, including for rush hour, additional passengers, luggage, high fuel costs and snow emergencies. Those charges were also used for zones.

Fenty's statements, made at the corner of 16th and U Streets NW, prompted cries of "No!" and "You're a liar!" from some of the estimated 50 people who crowded around the temporary podium. Many in the crowd were cabdrivers opposed to the change.

The Taxicab Commission will accept public comments on the new regulations over the next 30 days, officials said. The regulations are scheduled to take effect April 1.

Taxi inspectors will conduct spot checks around the city. Drivers who do not comply with the new system will be subject to fines of $1,000.

Fenty announced two weeks ago that the city would change from the 70-year-old zone system to the much more common meters. He said he is trying to polish the city's image and make it easier and more predictable for both residents and visitors to travel around the District.

"We appreciate everyone's position on this matter. In a city like the District of Columbia, it's not strange to expect differing views," said Fenty, who arrived at today's news conference in a cab. "In running a city, a decision has to be made, and we have made a decision."

Ward 1 D.C. Council member Jim Graham said he would hold a public hearing "to assure the public's engagement in these very important questions. We've got to have that."

But Aklile Redie of the D.C. Professional Taxicab Drivers Association said that he did not think the process was fair. "I do not know how this can be decided only by the mayor and the [taxicab commission] chairman," he said. He added, "We have so many things to fight."

The unveiling of how and when the meters will be implemented comes just hours after a strike by some cabbies{vbar}http://www.washingtonpost.com/wp-dyn/content/article/2007/10/31/AR2007103100617.html who oppose the change. Their 24-hour work stoppage ended at 6 a.m. today.

During the strike, there were noticeably fewer cabs on the streets and longer than usual waits at the taxi stands at Union Station and downtown hotels.

But many major hotels arranged for extra private cars and airport shuttles, and the strike did not visibly paralyze the city.

Staff writer Debbi Wilgoren contributed to this article.