It's not wasps in the garage that bother me, it's wasps in the house. They winter over somewhere in the house and then in the spring get into the living area. I suspect they may be in the attic and come to the light down the wireing through some light fixtures in the evening. I don't want to kill them because they eat undesireable insects, of which we have a big supply. It's a challenge to get them out of the house. Have some success putting a broom in front of them and getting them to crawl on it, then take the broom outside and shake the wasp off. Also throw a towel over them and fold the towel over them, the shake the towel out. Got stung through the towel own day last week. I'm not sensitive to stings but sure don't enjoy them.
I think like another poster said, they just go to the garage looking for insects.
KEH