Alien Invader Observation Journal: Number 93

Alien invaders on Earth are, as a general rule, excellent drivers. However, this only follows if the alien invader is alone in the automobile.

Due to their telepathic nature (see Alien Invader Observation Journal: Number 43), the more alien invaders in a single vehicle decreases the efficacy of their driving ablilities.

Two alien invaders in a car together may be seen moving in an erradic fashion (weaving in the lane, failure to propperly signal at every intersection, etc.), but four or more alien invaders in a car together becomes downright scary. Instances of random lane changes, disregard for rules of the road and intermittent speed changes result from too many alien invaders all trying to control a machine at the same time.

This accounts for the high incidence of alien invaders gaining work as taxi drivers versus the low incidence of alien invaders as bus drivers. Alien invaders are far more likely to take a cab than to ride mass-trasit, knowing that the danger to themselves and others is lower if there are fewer of them in a single vehicle.