Ottawa drivers who leave their engines on and their tailpipes puffing while they aren't driving could soon face a $100 fine.

An Ottawa committee will consider Tuesday a bylaw that would ban idling for longer than three minutes except under special circumstances.

Susan Jones, the city's director of bylaw and regulatory services, said the proposed bylaw is aimed at protecting health and the environment, and is modelled on existing laws in Toronto and Montreal.

It is targeted at people such as parents or spouses waiting to pick up a member of their family or tour buses waiting for passengers outside hotels.

"This is really a common-sense approach. It's really not necessary to idle your vehicle," Jones said, adding that shutting and restarting the engine requires less fuel than 10 seconds of idling and saves money.

She added that the bylaw would include exceptions for drivers stuck in traffic, as well as those trying to keep warm on days colder than 5 C or trying to keep cool by operating their vehicle's air conditioner on days hotter than 27 C.

If the bylaw is passed by the city's planning and environment committee, it would go to city council on May 9. If passed there, it would be phased in starting September.

"This year if the bylaw is enacted we're going to work on education first, and only warnings would be issued," Jones said, adding that the public would be notified before the city began hitting idlers with a $100 fine in 2008.