ther are nesting in your engine bay. a long drive with all the vibrations should chase them out of there but eggs will still hatch. i get them sometimes form y girlfriends house, they liked to get intot he mirrors of my car and stay there tilli got home, happened 3 times to me that i'd wake up in the morning to these spiderwebs between my doorpanel and the mirrors, and the anchor spots were a bish to look at.