The state Division of Public Utilities and Carriers on Friday yanked the license for half of Yellow Cab’s fleet and fined the company $100,000 for rolling back odometers on its cabs.

The rollbacks did not affect the fares paid by customers, but allowed Yellow Cab to keep the taxis on the street after their mandated retirement at 200,000 miles. That allowed the company to lower its costs while carrying passengers in vehicles considered too old for use as cabs.

“The basic principal is to make sure the riding public has a safe and relatively new vehicle,” said Thomas F. Kogut, spokesman for state agency.

Carol Allen, president of Yellow Cab Inc., could not be reached for comment on Friday.

Yellow Cab, which acknowledged sufficient evidence of its misconduct, also was cited for record-keeping violations, for charging illegal flat rates for fares, rather than mileage-based charges based on the taxi meter, and for operating outside territory of Providence, Cranston and T.F. Green Airport.

The division does not oppose flat rates in principal, Kogut said, but all taxi rates in Rhode Island are based on mileage. The division does not want companies deviating from the approved mileage-based rates because it could lead to some customers being unfairly charged higher rates.

The restriction on territories is intended to balance the number of cabs operating in an area with the public need for taxis there. “You don’t want to create an environment where you have destructive competition,” Kogut said.

All taxi rates in the division’s jurisdiction — all of Rhode Island except Block Island — are uniform, so all customers should pay the same amount for the same ride. The only way cab companies can compete against each other is in the quality of service they offer. Statewide, about 80 companies operate about 225 cabs on any given day.

Although Yellow Cab had licenses for 12 cabs, it was operating only seven when the enforcement action was taken. That means losing half of its licenses will reduce the operating fleet by one, to six.

The company, which is also on five-years probation, has to pay its $100,000 fine in yearly installments of $10,000. If it stays out of trouble during the probation period, the $50,000 left at that time will be waived.

pparker@projo.com