Warming up your car is illegal in Ohio.
via the Ohio Revised Code,
In other words, anyone who leaves a running vehicle unattended, even if he or she is just stepping away while it warms up, can be charged with a misdemeanor and a $150 fine for omitting to stop the engine, lock the ignition, and remove the keys (emergency vehicles exempt).
It also states the parking brake must be set (does anyone really do this?) and the wheels must be turned to the curb if the vehicle is left on a grade.
Since the law does not specifically exclude private property from this statute, you can be cited for leaving the car running in your very own driveway.
The folks from the Ohio Insurance Institute reckon the law's been put into place to deter thievery, though environmental issues are another speculated concern.
Regardless, of rational, it's bogus that we have either have to A) wait in or next to our cold cars while they warm up or B) drive our cars cold, especially since northeast Ohio winters are particularly frigid.
Based on the wording of the statute,
The law remains in effect until 2017.