I recall truckers complaining that their rigs got worse mileage at 55 than 65 because of the gearing.
I know my Honda Pilot shifts into 'high' at 62 mph.
At 55 I would be stuck in a lower gear and likely burn more fuel.
Cruising an interstate gets better mileage plus it is less wasteful on one's time.
Getting to a job promptly or completing a job promptly makes more logic than sitting at 55 mph.
( assuming good tires, weather, traffic...)
"I recall truckers complaining that their rigs got worse mileage at 55 than 65 because of the gearing."
That doesn't make sense. Trucks have tons of gears, closely spaced. If 55 was too low for top gear they could easily drop down a gear or two and be running the same rpm as at 65.
"I know my Honda Pilot shifts into 'high' at 62 mph.
At 55 I would be stuck in a lower gear and likely burn more fuel."
Weird. The 5 speed automatic in my Accord has switched up to 5th and the torque converter locked up by the time I reach about 45 mph, if just cruising on a level road.