21710 CVC The driver of a motor vehicle when traveling on down grade
upon any highway shall not coast with the gears of such vehicle in
neutral.

To answer your question, you need to be in neutral to coast while having the vehicle off. So this would be a good section to cite for.

 

Now if only we could find a way to make all roads just run downhill.

 

NEVER heard of that law. In my city, people are so lazy they create traffic jams because they take too long to move at the light. It's normal for me to be five cars from a red light and it turns red again before I get there because everyone isn't paying attention to the light. They're too "busy" barking on their cell phone or talking to the passenger or putting on makeup. I've never been in a line of cars when a fire truck or police car came along so I don't know how long they take to get moving. But they're very lazy drivers. Every accident I've seen in my city is caused by this: someone wasn't paying attention and rear-ends another car trying to get on/off the highway. (PS: to those drivers: you're supposed to DECELERATE when you exit the highway, not speed up!) And did I mention everyone drives 11 mph over the speed limit rain or shine, snow or not and half of the people entering the highway pass on right, sometimes even using the emergency lane? Some people just shouldn't be allowed to drive. My point is there are a LOT of other things to be more scared of than one person trying to save gas. And half of the people I meet at intersections with stop signs don't know the basic rules of yielding.