Why do we pull off to the side of the road when we meet a funeral procession?

The history of the practice of pulling off the road during a funeral procession, was at one time, a law.

Now only regarded as a "practice" for those who wish to pull off the road.

Back in the early days when automobiles were a new form of transportation and roads weren't wide enough to accommodate the width of a car and a horse drawn hearse meeting one another, automobiles were required to pull off the road and be shut off.

This allowed for the procession to proceed as a whole and the horses not to become spooked by the car engine.

It was never intended to be regarded as a "respect for the dead" issue.