It might be tempting to pull up to the drive-thru window to fill up on food and coffee on frosty winter mornings, but some Canadian communities are arguing that traffic safety and concern for the environment should trump convenience.

At some popular fast-food restaurants across the country, lineups are so long they stretch out of parking lots and spill onto public streets, and politicians are eyeing the emissions spewed by all the idling cars, trucks and sport utility vehicles.

In London, Ont., civic leaders are considering restrictions on existing drive-thrus to try to clear the air. A citizens' advisory committee is also recommending a moratorium on new drive-thrus, although the mayor is trying to strike a balance.

"I don't support a ban or a moratorium on drive-thrus ... but if there are ways in which we can improve the air quality in ways that I can't imagine at this point, I'm really open to looking at that and seeing if we can strengthen our bylaws," says Anne-Marie DeCicco-Best.

London council is gathering public input on a range of options, from banning new outlets to tightening zoning bylaws to make more areas of the city drive-thru-free. City staff have floated the idea of restricting the hours of operation for drive-thrus, and a decision is expected in the new year.

In Hamilton, Ont., where Mayor Fred Eisenberger describes himself as "reasonably anti-drive-thru," council is studying an environmental group's call for a moratorium on new drive-thrus.

In Kings County, N.S., one politician has argued that only people with decreased mobility should be entitled to get their food while in their vehicle.

"I think a pregnant mom or a disabled person or a person who couldn't get out of their vehicle or an older person, they could use the drive-thru," says Wayne Atwater. "But these people that are able-bodied men and women, I certainly don't see any reason why they can't get out of their vehicle."

Atwater pushed for a moratorium on new drive-thrus last winter, citing concerns about carbon monoxide and traffic problems, but he couldn't persuade his council colleagues.

Communities from Toronto to St. John's, Nfld., have taken steps to ensure that drive-thrus are far from certain residential streets or big enough to fit a long lineup of cars. But it's the increasing worry over greenhouse gas emissions that's prompting a second look.

Students at the University of Alberta monitored a popular Tim Hortons outlet in Edmonton last year for 54 hours and counted 3,756 vehicles idling for an average of more than five minutes each. The longest idle was more than 12 minutes.

Tim Hortons's drive-thrus tend to generate the most attention because of their popularity. In Winnipeg, cars spill out of Tim's lots onto such major thoroughfares as Portage Ave. and St. Mary's Road as drivers queue up for a java jolt.

"They're victims of their own success," said Winnipeg councillor Mike O'Shaughnessy. "You can see 15, 16 cars in line at three in the afternoon or seven in the evening."

Winnipeg has rejected two proposals for Tim Hortons this year. One was nixed because it would have interfered with a driveway of an adjacent business. The other was axed because nearby residents expressed concerns about traffic.

But O'Shaughnessy says those were individual cases and Winnipeg has no plans to crack down on drive-thrus. "We're not against Tim Hortons. We're not against drive-thrus," said O'Shaughnessy. "They're very popular."

Tim Hortons says it has taken steps to reduce drive-thru lineups, such as allowing motorists to use credit cards that don't require signatures. Many drive-thru work stations now have their own coffee maker and other equipment, so attendants don't have to walk to another part of the shop to fill an order.

The company also says it meets or exceeds space requirements in city bylaws. "We tend to find sites that are a little bit larger so we can accommodate a big parking lot and have a larger than required drive-thru," said Tim Hortons spokesperson Rachel Douglas from the company's headquarters in Oakville, Ont.

"(Drive-thrus) are almost becoming a bit of an essential service. You have parents with young children, you have elderly people with mobility issues. We find that our customers are wanting drive-thrus and are using drive-thrus and that's really what's behind the demand."