Have you heard of this 'boy racing' bylaw?

A sign in New Plymouth informing motorists of a light vehicle restriction bylaw which was deemed too small. Photo/ Supplied

An unusual bylaw banning cars from certain streets overnight is being used in several cities around the country to crack down on boy racing.

But despite being in effect for years, few people may realise they exist.

While each council has devised its own specific bylaw, all are designed to keep light vehicles - those under 3500kg - off the roads overnight in what are generally industrial areas.

There are exceptions for emergency and trade vehicles on the job.

When the ban was on rural roads, exceptions were also made for residents, a Christchurch City Council spokeswoman said.

The bylaws were a response to congregations of boy racers meeting in quiet areas overnight to not only run drag races, but also participate in other illegal behaviour, including drug taking and sexual assault.

New Plymouth has implemented the bylaw since 2009 with success - but it recently caught out unsuspecting motorists using roads in prohibited hours for legitimate purposes.

Brady Whale and several other friends were given $750 fines earlier this year for using Corbett Rd in Bell Block, north of New Plymouth between the hours of 7pm and 7am.

"I was just going from Lepperton to back home, not causing any trouble," he told Fairfax.

The group had been heading for a service station at the time.

Whale was able to get out of paying the fine by successfully arguing signs informing road users of the bylaw were not large enough. His friends, who had already paid their fines, were now trying to receive refunds using the same reason.

"We're fixing this situation by having new signs made and they will be delivered in the next few weeks," council customer and regulatory solutions manager Katrina Brunton told the Herald.

New Plymouth Road Policing Supervising Sergeant George White said anecdotally he remembers handing out about 20 tickets a week when the bylaw was first implemented, and in combination with other measures it has largely worked in cracking down on bad behaviour by boy racers.

"One of the problems we had was huge gatherings out there and people couldn't get into work.

"And it wasn't just car enthusiasts, it was people taking drugs, there were sexual assaults out there," he said.

"There's no problem with people and kids being enthusiastic about cars - it's when they start doing illegal and antisocial things, that's when it becomes a problem."

A sign in Auckland warning motorists of light vehicle restrictions. Photo/ supplied

The bylaw had also had success in reducing unruly behaviour in Christchurch and Porirua, which has been enforcing the bylaw for at least a decade, a police spokeswoman said.

"The bylaws, along with other measures such as speed bumps, have been successful in removing the large volumes of illegal street racing from those particular streets."

Police are the body to enforce the bylaws and officers are the ones to hand out tickets.

To find out the number of tickets handed out in each region, an Official Information Act request would need to be lodged, the spokeswoman said.

Auckland enforces its bylaw on eight different roads in industrial areas, banning light vehicles from using those roads between the hours of 9pm and 4am, Auckland Transport spokesman Mark Hannan said.

Hamilton had the ability to enforce this kind of bylaw but so far had not done so, said city council network operations team leader Robyn Denton.

"We have a range of measures we employ to deter anti-social driver behaviour - these include road design and speed limit management, and we work closely with Waikato Road Policing units."