Since the change is new — it was approved by the Madison City Council on Tuesday — Bach said an enforcement protocol is still being developed and said tickets will largely be complaint driven.

“I think we have to exercise some kind of common sense and reasonableness here on how we go about enforcing this,” Bach said.

Several exceptions to the time limit are built into the law.

People may idle vehicles to use their defrosters, air conditioners, heaters and other equipment to “prevent a health or safety emergency, including for the purpose of providing shelter.”

Drivers are also exempt if the outside temperature is below 20 degrees or above 90 degrees. Actively loading and unloading passengers or property on private property while idling is another exception.

Idling in congested traffic, for repair or service work, and for using equipment attached to a vehicle, such as a crane or concrete mixer, is also excluded from enforcement.

“We’re not going to go out and start laying tickets on these vehicles without looking at the bigger picture here of how long they’ve been idling, why they’re idling, whether the person maybe wasn’t aware of the ordinance,” Bach said.