Highway miles are the easy miles
Almost everything written about service intervals is about what shortens them. There is a case on the other side, and a vehicle doing long highway legs is the one it applies to.
An engine at a steady cruise is in close to its ideal condition. Fully up to temperature, which means moisture and combustion byproducts are being driven off rather than collecting in the oil. Running at modest load. Not being restarted repeatedly, which is where a good share of engine wear actually happens.
A hundred highway miles are genuinely gentler on oil than ten miles of cold short trips. Which is why a long-distance vehicle can reasonably sit at the longer end of its manufacturer's range, while a vehicle doing a few miles each way in town belongs at the shorter end, even though the first covers ten times the distance.
The mistake is treating all mileage as equivalent. It is not, and on a highway vehicle it works in your favor for once.
What still shortens it here
Two things, and both are local.
Dust. Fine airborne material is hard on an air filter and gets past a compromised one. The air filter matters more here than the schedule suggests.
Heat. High ambient temperatures mean oil runs hotter, and heat is what degrades it. That partly offsets the highway advantage above, which is why the answer is the manufacturer's range rather than an invented figure.
Towing and idling, as always, shorten it further. The national oil change page covers how those work.
While it is up
Tread depth and wear patterns, brake condition, leaks and suspension components. On a vehicle about to do a long run, those checks are worth more than the oil. See scheduled maintenance.
About this store
The Fernley store runs sixteen services, carries all nine Purcell tire categories, and is managed by John Jangula.
See the national oil change page for all 33 locations.