Well, 由 the book nothing will happen if they eat something, in Twilight Edward took a bite of 比萨, 比萨饼 if i remember well, so maybe it's not a flaw in a movie, they just tried to 显示 how r they tryin to blend in with humans...
Well, there's a possibility that his car is adjusted for ppl who can't walk, all of the operations are hand controlled, in my country there are loads of cars like that, I've seen those...
Yes I agree with Bella0405...disabled people can drive...the brake and the gas peddles are turned into hand controls that up close to the steering wheel..my uncle 迷失 his legs years 以前 and still drives to this day...:)