For many years my family has been driving from New York to various states for vacation (Florida, Ohio, Virginia, etc.). We love roller coasters!
This question has been bothered me for quite some time: If while driving, whenever possible, you change lanes and take the ‘inside’ lane around the curves, do you save a significant amount of mileage/gas/time over the course of the entire trip?
Of course you would only change lanes when it was ‘safe’ to do so.
I am confident this is a question that the wise ones at Straight Dope can handle.
Please help me!!! We are in the process of planning another trip.
Thanks.
Well, it shouldn’t be hard to calculate that. Assuming the majority of the roads are 2-lanes each way, the distance between the inner and outer lane is at most 5 meters. If the road curves by angle A, the path difference between the two lanes is 5piA (assuming A is in radians). So for a 1-radian (57 degrees) turn, you save about 15 meters in path length. The question is, how far do you have to drive till you turn 1 radian (60 degrees or so)? Or how often do you encounter a 1-radian corner? If you take twisty country roads, I think it can be as little as a kilometer. If so, by always taking the inner lane, you’ve saved 15/1000=1.5%. If your car’s gas mileage is normally 20mpg, you will improve it to 20.3mpg.
I think most roads are far less twisty than that, so I think a reasonable answer is “the difference is 1% or less”. I wouldn’t worry about such a small difference myself.
Not if you changed lanes when you turned right. It would even out if you were in the same lane the whole time, but not if you always switched to the inside lane.