Have you ever considered the growing possibility that we may be idling more than is legally allowed? It would be great to know which states have emissions related idling statutes and how long is too long when it comes to idling in your area. Luckily, the American Transportation Research Institute has done the work for us.
According to their Compendium of Idling Regulations many states have legal idling limitations. The map below outlines which states have idling laws prohibiting the amount of time a vehicle can remain running.