App. 5 yr. old Shepherd mix, she has had anxiety problems, but even after a long day (ex., a trip to Vashon) tons of fun and playing w/ other dogs, eventually she will throw up. I have heard that feeding ginger can help and my sister even told me that dogs who get carsick are helped by the bumper strips that trucks use to ground electricity but that seemed so far fetched that I haven't tied it yet.

yeah, it sounds like she is carsick

He is carsick - poor guy.
If you know you are going on a car trip with him don't feed him within 2-3hrs before leaving - he'll just throw it up in the car. I have also heard that putting a chain or bumper strip off the end of the car to reduce electricty does help.
Now,dogs can have Gravol - but be a smartie and get the okay from your Vet before you run out and buy it. S/he'll give you the correct dosage. Note: gravol will also make him groggy.