My Gucci does it too. When we going in the car or when he knows I am leaving the house. He starts to shake from the time I'm getting dressed.
(Wait did this dog just pass wind next to me???
...
es:....Lord the things you accept from these animals....LOL)
Anyway...back on topic.
However once in the car he sorta inda stops shaking unless I turn on the indicator (he barks at that) or a motorcycle or loud car passes by.
I do not drive with the windows down...
He doesn't like his booster seat either.
He tries to jump on my lap and when he doesn't accomplish that he lays in one corner (face hidden) of the booster seat for the whole ride.