Here in Toronto, a large funeral procession ( more than 50 cars in total ) requires a Police escort of patrol cars by city by law. The funeral home contacts the Toronto Police Service , requesting at least 3 patrol cars, some time more. The officers driving the cars are on "days off " and the cars being used are fleet spares that are not assigned to a particular Division.
The minimum time period for such a "Paid duty " is 4 hours pay to each officer. The funeral director pays the invoice from the TPS, and the TPS pays the off duty officers, minus taxes. The lead Police car stops at each intersection, the officer gets out and stops ALL traffic, the procession approaches the intersection. The second patrol car takes over the intersection and the lead car goes ahead to the next intersection. The last patrol car stays at each intersection until the last of the funeral cars goes through, and make sure that no other cars are "tagging along" . On a busy week day in Toronto, there could be three or four such funeral processions that require a Police escort group.
I will point out that Toronto is by far the largest metropolitan area in all of Canada, with a population of more than 4 million in the Greater Toronto Area. Hence the requirement for Police escorts for large funeral processions. A long time ago, when I was a young man, I worked for about a year for one of the Jewish funeral homes in Toronto. The largest funeral procession I saw back then was over 400 vehicles for the funeral of a very well known Politician named Isadore Singer. JimB.