It's about time more cities did this.
Where I live, the law against leaving a car running for more than one minute is probably the most ignored in the City, although with Toronto police it is hard to tell which car-related law they don't ignore. Other cities are tougher; in New York, there is a reward program for tipsters that pays out 25 percent of the fines and people are making good money snitching.
In London, they have had anti-idling laws for years, but drivers got a warning first, and could only be fined if they ignored it and stayed put for another minute. That's now been changed, and they are cracking down; according to the Times,
Drivers could face a £20 on-the-spot fine for leaving engines running when parked. All 32 London boroughs will step up enforcement of engine idling, with council officers challenging drivers. Volunteers will also be recruited to take part. The scheme will begin in the City of London from today before spreading to the rest of the capital.
Letting an internal combustion engine idle puts out a lot of pollutants; according to the Times, emissions in congested areas could be cut by 30 percent by turning off engines of cars that aren't moving. According to the Guardian, "an idling car produces enough exhaust emissions to fill 150 balloons a minute" which is kind of meaningless.
In Canada, you can look at every Tim Horton's crawl-thru and see dozens of SUVs and pickups idling in line. According to Natural Resources Canada, 10 min of idling of a 5 litre engine burns half a litre of gasoline, which emits 1.15 kilograms of CO2, along with Nitrogen Dioxide and particulate matter. They are not strictly idling given that they are in a slow-moving line, but the damage is being done nonetheless. NRC says, "If you're going to be stopped for more than 60 seconds – except in traffic – turn the engine off. Unnecessary idling wastes money and fuel, and produces greenhouse gases that contribute to climate change."
It would be nice if the police would actually enforce anti-idling laws, particularly around school pickups. It would be nicer if we didn't have big SUVs and pickups with big gasoline powered engines in our cities. That's one good thing you can say about electric cars; they may be just as bad for traffic and congestion, but idling isn't an issue.