Hey there my Crab Camaro friend, that's quite the problem! Obviously, getting them out of the car is the biggest and trickiest problem, so let's start with solving the 2nd half of the problem first. What are you going to do with them once you get them out of the car? For this you should get several really big buckets. Once you get them into the buckets, they will be continuously pulling each other back down into the bucket while they try to climb out. They won't work together because none of them will want to be the ones stuck in the bucket at the end. Now, as for getting them out of the car, this is actually an interesting one. As it turns out, crabs are heavily effected by electromagnetic fields. Essentially, if you can get one of those magnets from a scrapyard, the crabs will basically be hypnotized and not move. The crabs will be attracted to the field, and will just sit still. You would need a larger scale, but even a fridge magnet is more than powerful enough of a magnetic field to hypnotize them.