Drivers could be prosecuted for letting their engines run at a Tayside pollution hotspot.
Council bosses are considering issuing fines to “idling” motorists on Crieff’s High Street.
It is part of a package of measures proposed to combat long-standing air pollution problems in the busy town centre.
The area, along with Atholl Street in Perth, is one of Scotland’s most polluted streets.
Perth and Kinross Council has come up with an Air Quality Action Plan for the market town, looking at ways of reducing congestion and emissions.
The paper, which will go before councillors next week, proposes a study of traffic flow, a parking shake-up and new traffic control systems.
Gating or holding traffic outside of the High Street “canyon”, as well as limiting or prioritising traffic turning right into the thoroughfare, will also be considered.
And it is further proposed that “anti-idling enforcement” could be introduced, which if approved would be among the first of its kind in Scotland.
In her report, council officer Kirsty Steven suggests: “Perth and Kinross Council will consider the adoption of powers to undertake enforcement through Traffic Regulation Orders to compel drivers to switch off idling engines.
“Fixed penalty notices could be issued to drivers who refuse to co-operate.”
Scottish road traffic regulations allow councils to apply to the government to tackle problems with engine fumes running “unnecessarily”.
Earlier this summer, Inverclyde Council asked the Scottish Government to introduce such measures.
Graham Donaldson, who chairs the Crieff Success BID board, had mixed feelings about the proposal.
“I’m not sure how effective this would be,” he said.
“Most modern cars these days automatically cut off when they come to a stop.
“What would really make a difference is if they found a way to move the buses off High Street, maybe down into the square.
“They are sitting out there idling constantly. They definitely appear to be the worst offenders and worst polluters.”
“The buses we get out here are full diesel as well, we don’t get the hybrid vehicles you see in Perth.”
Mr Donaldson, who runs the Gordon and Durward sweet shop, added: “I have to admit that we also cause congestion by loading and unloading into the business. I have to take everything in through the front door, because we don’t have an alternative.”
In her report to go before the council’s environment and infrastructure committee, Ms Steven explains the problem, writing: “High Street which runs through the centre of Crieff is a narrow street with tall buildings either side of the road.
“This has resulted in a canyon effect which prevents air pollutants from dispersing. The
narrow road often becomes congested, particularly at peaks times throughout the day.”
Although described as one of the most polluted streets in Scotland, Crieff High Street actually dropped out of the top 10 worst offenders’ list this year.