The safe operation of most vehicles relies on minimal distractions for the driver. A spider loose in the car is worse than having an axe murderer in the back seat. The very thought that a spider might crawl up on your hand or descend down onto your face at any moment is almost worse than it actually happening and not crashing the car suddenly drops to a distant second priority compared to keeping that thing away from you. Spiders. They're great, until they can touch you.