I was looking up some service interval information for my '03 Honda Accord
today and noticed that Honda says for US customers to use the normal service
schedule unless certain conditions are met (frequent short trips, etc. etc.)
but that Canadians should always use the severe service interval schedule.
This correlates to oil changes every 7,500 miles for US residents but every
3,750 for Canadians?

This is rather peculiar to me. Ontario is by far the most populated province
of Canada and it's climate is largely similar to that of Michigan, Upstate
New York, Vermonth, New Hampshire and Maine. Prevailing weather conditions
are not enough to explain Honda's doings.

Does this have something to do with different fuel formulations in Canada,
or is it more evidence of things other than good engineering being behind
Honda's recommendations?

John