I realize we've had similar posts about this...but since that dog died recently in a car (was it in CA?), I thought it may be good to discuss this again.
Here in AZ, if there is an animal in a hot car - even if the windows are cracked - we can call 911 and the police will come. They'll park their patrol car behind the offender's car and wait for the person. If the dog is in bad distress, they'll break a window.
I have called 911 several times for this here in Phoenix, and they've come within 5-10 minutes. When you call, be sure you can give the address - or the cross streets.
Do you know your law?