Police on Monday fixed acceleration limits for 85 city streets to curb drivers’ need for speed, but stepping on the gas should still be easy with a mere six speed radar guns installed across the city.

“Keeping in mind the safety of the public at large, this is a move to instil a uniform pattern for movement of vehicles along some of the key roads. You need to specify the speed limits first before you prosecute someone for overstepping it,” the deputy commissioner of police (traffic), Manoj Verma, said.

Roads have been divided into three categories, based on their condition and density of traffic. But what could make enforcement almost impossible is that the speed limit on a particular road will be different for a car, a bus, a heavy goods vehicle and a two-wheeler.

For instance, a small car, a sedan or an SUV can be driven down EM Bypass at a maximum speed of 60kmph, but a two-wheeler and a “heavy passenger vehicle” cannot exceed 50kmph. The upper limit on Red Road is 50kmph for a car.

Verma didn’t specify any change in the enforcement plan, which means people at the wheel who know little about the rules of driving in a metro — especially changing lanes in high-speed corridors — can still get away without so much as a reprimand.

The police had installed cameras at a few intersections last year, but there are no records of how many people have been penalised, if at all, on the basis of the recorded footage.

Senior police officers admitted in private that they doubted whether speed limits would ever be enforced. “For all the hype about the cameras, they made little difference to policing. The traffic guards that were created to rein in rogue drivers have not been able to deliver because most of these units are understaffed. Even the moveable display boards that were installed have not been effective,” they said.

Another officer said the city would need speed radars on every road and a stringent system of fines for people to adhere to the acceleration limits. The lack of traffic policing after 10pm, when speeding is the norm rather than the exception, is cited as a reason for the failure of previous initiatives.

The officer said traffic-violation penalties needed to be increased. “It has been decided that for light motor vehicles, the first penalty for a speed violation will be a fine of Rs 300, followed by Rs 400 and Rs 500 for the second and third offences. These amounts are hardly a deterrent, and there is no way to find out instantly if the driver has erred for the second or third time,” the officer said.