saywhatyoythink, this law is closer to your home than you may think.  The new law prohibits smoking in all motor vehicles “In which a person under eighteen years of age is present.”  It makes no mention of where the vehicle must be to be in violation.  The intent may be on public roads, but that is not how it reads.  As it reads, you could be in violation for smoking in a vehicle parked in your own carport.