The route/highway argument is similar to the pop/soda argument, in that it bepeaks differences in regional dialects. But, it's a little more nuanced because it's less of an argument than a semantic difference.
On parts of the East Coast, people call highways "routes," but only in a specific circumstance. They might call it "Route 495," but then they will refer to "Route 495" as a "highway" when saying something like, "I live just a few miles from the highway." Thus, unlike the pop/soda argument, the East Coasters agree with the West Coasters on what the thing itself should be calledâ€”"highway." It's just that when some East Coasters refer to one of these highways by its number, they say "Route ___."
It's also worth noting It is helpful to know the logic behind road numbers because this logic can help you navigate when you are sort of lost.
Major roads that circumscribe a city have three digits. Thus, 495 circumscribes Boston.
Major roads that run east/west have an even number. Thus, 2 runs from Boston out through Williamstown and beyond. Similiarly, 66 runs horizontally across the country.
Major roads that run north/south have an odd number. Thus, 95 runs from Montreal down to Florida.
So, if you ever find yourself completely lost, you can sort of navigate by the road number. Sort of..