How to Drive Efficiently On The Freeway

Next time you go driving, stick your hand out of the window and feel how the wind resistance varies between 30mph, 40mph, and 50mph.  Air resistance transforms from being a negligible force to a very powerful one after 50mph because that force gets bigger as the car goes faster.  This drag is negligible on the street but on highways, air resistance is a very significant force your car is battling against.

More than 60% of the power required to cruise on the highway is used to overcome air resistance.  Maintaining a low speed of 55mph causes your engine to sip fuel relative to higher speeds.  You’ll feel how lightly you need to keep the pedal pressed to maintain 55mph.  The engine also spins at a lower speed (RPM), effectively reducing wear, increasing longevity and polluting the air a tad bit less.

Driving becomes sooooo easy at 55mph, so much so that I swear it literally feels like time slows down. My mind doesn’t get caught up in the hustle and bustle of getting from point A to point B.  Instead it unwinds and disengages from the process, very much like meditation.  Overall ride quality is more comfortable because the bumps don’t feel as harsh.  Wind noise is less, road noise from the tires is less and the engine is also quieter.

Going 55mph in the slow lane with the cruise control on makes driving very passive.  So passive in fact that my subconscious takes over and I can just disconnect and relax.  There’s something very calming about taking it easy while all the other cars are whizzing past you.  You may feel this similar effect when everybody is driving slow when it’s raining and the flow is much more relaxed.

I would even recommend you try this for the relaxing-effect more than the gas-savings!  It really is that therapeutic and errands are less tiring.

This is a very good question… and the answer is NOT REALLY!  Driving slow doesn’t seem to affect arrival time by more than a couple minutes because the time it takes to arrive somewhere depends on the average speed, not how fast I was trying to go on the freeway.

If I am driving 55mph in the slow lane, I can generally maintain that speed on cruise control until I need to exit.  The need to brake is very rare and slower cars do not get in front of me.  I can maintain an average speed of 55mph effortlessly.

On the other hand, If I am trying to maintain a speed of 75mph, my average speed will be lower than that because I am constantly at the mercy of other drivers.  Even if I am in the fast lane, I may come upon somebody going slower than me and have to slow down.  I may have to switch lanes to speed up again.  When it comes time to exit, I need to slow down and make my way over to the slow lane.  Often the flow of traffic may be too slow to maintain 75mph.  All of these scenarios decrease average speed.

For that reason alone, even though I am trying to drive at 75, my average speed may be closer to 65mph.  That 10mph difference for the freeway portion of the trip is not very significant, especially for the amount of extra hustling that’s being done.  On a 10-mile trip, it will take only 1 minute and 40 seconds more to get to your destination if you’re driving at an average speed of 55 instead of 65.  And this is only taking into account of my time on the freeway. In reality, we drive a mix of freeways and streets.

So let’s say the time has come to exit the freeway and we have to wait at a red light.  Sometimes this light may take over a 1 minute to turn green!  Traffic signals are the great equalizer, constantly penalizing (and ridiculing) those who speed.  Those couple minutes that are saved by speeding may be totally negated by a few badly timed traffic lights.  It’s not uncommon to see cars that were speeding passed me to be stuck at the same light as me.

Anytime I fill up my tank completely, I have a habit of resetting my odometer.  That way I know how many miles I’ve driven on a full tank when it is almost empty.  After I started driving slower on the freeway, my fuel efficiency shot up from 300 miles to 360 miles per tank.  That means I went from 25mpg to 30mpg with my 12 gallon tank.  In other words, I increased my fuel economy by 20%! That tiny change allowed me to drive 1-3 days longer without having to fill up.  Since then I’ve pushed my efficiency practices even further and have gotten 420 miles on a tank several times.