Neil Gerace writes:

The opposite, as it happens. Believing that cars were the dominant
life-form on the planet, he picked the name Ford Prefect so as to
blend in.

"This friend of his had first arrived on the planet some fifteen Earth
years previously, and he had worked hard to blend himself into Earth
society - with, it must be said, some success. For instance he had
spent those fifteen years pretending to be an out of work actor, which
was plausible enough.

He had made one careless blunder though, because he had skimped a bit
on his preparatory research. The information he had gathered had led
him to choose the name 'Ford Prefect' as being nicely
inconspicuous."

MJ