Is It Illegal to Warm Up Your Car in Missouri? – Depends
It is possible that you might be a law-breaker and not even know it. Do you warm up your car without you in it? It's actually illegal, but there is an exception.
I found this article on Reader's Digest that was recently updated as laws are changing. The issue is car idling during the cold weather months. On their list, it shows that warming up the car in winter in Missouri is illegal.
What is the problem with warming up the car without you in it?
It's not for the reason you think. My guess was that it was to try and reduce auto thefts since keys in a running vehicle without a driver is an easy swipe for a criminal passing by. The truth according to the Reader's Digest article is that it's harmful for the environment. You can see this, but I'm rolling my eyes right now.
What is the exception?
Since technology has advanced a lot in the past decade or so, remote start is now an option for many newer vehicles. C-Net says that it is OK to warm up your vehicle if you have a remote start system that does not require the key in it.
Do I believe that it's extra harmful to the environment? Nope. I'm sure there is a climate scientist shaking his/her head in disagreement right now. The interesting thing about the Reader's Digest article is it says that it does not help extend the life of your vehicle by warming it up and can actually hurt it. I would have guessed the opposite and apparently been wrong. Go figure.