BEVERLY - The Ford Motor Co. is testing computer software for its police cruisers to prevent the kind of sudden acceleration incidents reported last year by Beverly police.

The software would make it more difficult for the car to speed up if the driver accidentally steps on the gas and brakes at the same time, the company says.

"You would have to be much more purposeful in stepping on the accelerator," Ford spokesman Daniel Jarvis said. "It would make that phenomenon less likely to happen."

Last year nine Beverly police officers and the head of the motor pool reported at least 13 incidents of sudden acceleration with the department's three new Ford Crown Victoria Police Interceptors, known as CVPIs.

One of those cruisers was involved in an accident that killed a woman last January. Patrolman Stuart Merry has been charged with negligent vehicular homicide in that crash.

All three cruisers in question are now off the road. The city replaced them earlier this year with three new Dodge Chargers at a cost of about $80,000.

Jarvis said a "very, very tiny fraction" of police departments across the country have reported instances of their cruisers accidentally accelerating. He said he did not know the exact number.

In every case that Ford has examined, Jarvis said, the computerized report from the "event data recorder" in the vehicles has shown that the driver was stepping on the gas pedal and brake pedal at the same time, either with one foot or two feet.

The new software that Ford is testing would prevent the car from speeding up in such cases unless the driver stepped very hard on the gas pedal, Jarvis said.

Jarvis said the company is only testing the software and hasn't decided whether it will go through with its development. Even if it did, he said, Ford would install the software on police cruisers only if police departments request it.

Jarvis said some police departments want to preserve the ability to step on the gas and brake at the same time in certain situations, such as trying to force another vehicle to spin out during a pursuit, or trying to get out of a snow bank.

"It still lets officers use two-footed maneuvers when they have to," he said.

The new software would be used only in CVPI models from 2005 and beyond, because the throttle in those newer models is controlled by a sensor. Instead of a cable connecting the gas pedal to the throttle, a computer sends a signal to open the throttle when the driver steps on the accelerator.

The new software would force the driver to step harder on the gas pedal to override the brake.

"It wouldn't be a drastic change," Jarvis said.

Merry's lawyer has blamed mechanical problems in the cruiser for the crash that killed a Beverly woman last January. The case has not yet gone to court.

Merry's cruiser was totaled in the fatal accident. The other two cruisers involved with sudden acceleration reports are sitting unused at the city garage, said Bradford Koch, foreman of the city's motor pool.

"They're collecting dust," Koch said. "We're afraid to use them."

Staff writer Paul Leighton can be reached at (978) 338-2675 or by e-mail at pleighton@ecnnews.com.