If you run your car's exhaust and sit still for more than three minutes, beware more effective enforcement of Hamilton's anti-idling bylaw.

Councillors have backed changes that add teeth to the environmentally minded legislation that has been on the books since 2007 but ineffective when it comes to charges.

"The public should be advised that if you have been, for no legitimate purpose, idling your car, you have a much greater chance of getting ticket," Coun. Jason Farr said after Tuesday's planning committee meeting.

The tweaks make idling for more than three minutes a parking offence under the Municipal Act that could land a set administrative penalty of $100.

Until now, municipal law enforcement officers have faced more onerous legal action through provincial court.

Officers had to identify drivers or whoever had "care and control" of the vehicle at the time of an offence, noted Rob Ustrzycki, project manager in the city's municipal law enforcement office.

Moreover, in many cases, by the time they responded to complaints, the drivers were long gone and so were witnesses, Ustrzycki said.

Since Jan. 1, 2015, out of roughly 330 calls for idling infractions, municipal bylaw officers have laid only two charges, a staff report noted. There have been no convictions.

But the changes mean parking officers — who are already afoot on city streets — can simply ticket licence holders and don't have to identify actual drivers.

That is a more efficient system, Ustrzycki said. "We're not changing the bylaw itself; just how we're going to enforce it. That's what it comes down to."