Assuming a “long drive” is at least 200 miles and most of the trip is on a highway without a lot of slow spots, you should save much more than 20 minutes a year regularly going 15 mph over.
With a lower highway speed limit of 60 mph, going 15 over will put you at 75 mph. In an hour, you’re 15 miles further down the road going 75 than 60 and it will take you 15 more minutes going 60 to get to that same spot.
Specific conditions will change the numbers, obviously. I’d consider both a few hundred mile drive and driving through NYC during rush hour to be long drives and they’ll have vastly different stats. By all means leave earlier but that Speedr app seems like it’s mathing wrong.
That math ain’t mathing.
Assuming a “long drive” is at least 200 miles and most of the trip is on a highway without a lot of slow spots, you should save much more than 20 minutes a year regularly going 15 mph over.
With a lower highway speed limit of 60 mph, going 15 over will put you at 75 mph. In an hour, you’re 15 miles further down the road going 75 than 60 and it will take you 15 more minutes going 60 to get to that same spot.
Specific conditions will change the numbers, obviously. I’d consider both a few hundred mile drive and driving through NYC during rush hour to be long drives and they’ll have vastly different stats. By all means leave earlier but that Speedr app seems like it’s mathing wrong.