Latest info from AAA notes that the speed limit while towing is all over the map (literally):
Check: Trailer Speed Limits - AAA Digest of Motor Laws
In this litigious age, getting into an accident when exceeding your equipment's limits (tires, weight, speed, etc.) may be very costly. Remember, the computers on vehicles record how fast you are traveling...
Saw this on a site:
While each vehicle reaches its optimal fuel economy at a different speed (or range of speeds), gas mileage usually decreases rapidly speeds above
55 miles per hour. Just slowing down from 65 mph to 55 mph can increase your miles per gallon by as much as 15 percent.
According to the U.S. Department of Energy (DOE), as a rule of thumb, you can assume that each 5 mph you drive over 60 mph is like paying an additional $0.21 per gallon for gas (at $3.00 per gallon).
So, the Fuel Economy Benefit of driving slower is between 7 and 23 percent. The equivalent gasoline savings is $0.21 to $0.71 per gallon.
Let's take two hypothetical drivers, Bill and Bob. They need to go 60 freeway miles from City A to City B. Both cars get 30 miles per gallon if the driver stayed at 55 mph, the posted speed limit.
Bill travels at 55, but Bob speeds and does 75 mph - wanting to get there sooner.
At 75 mph, it would take Bob about 48 minutes to reach the destination.
At 55 mph, it takes Bill about 65 minutes to reach the destination.
At 55 mph, Bill used 2 gallons of gasoline. At $2.80/gallon, that's $5.60 to drive the distance.
At 75 mph, Bob would use 2.5 gallons of gasoline. At $2.80/gallon, that would be $7.00 to go the same distance.
But it cost Bob $157.00 and he got there AFTER Bill! WHY?
Bob was ticketed for speeding! $150 is the average speeding ticket in the U.S. And if he had been going 80 or higher the fine could have been even more, and he may have had to appear before a judge, cited for reckless driving and even ended up spending some time in jail.
For me, even when not towing, I set the adaptive CC for 65 and enjoy the right lane.