PHYSICS IS FUN! THE JOY OF EFFICIENT DRIVING

  While I used to think the only way to have fun in a car was to take it out on the track, I have been shocked to discover maximizing miles-per-gallon (mpg) can be just as fun!  Yes… FUN.  I know most people might scoff at this idea, but please hear me out.  My revelation began about 3 years ago, when I bought my first hybrid.  As a fast car lover, friends and family were surprised I went with the “smart choice” instead of the “fast choice”. To be fair, the car was technically a sport-hybrid (Honda CR-Z), but that is beside the point.  The efficiency of the hybrid was pretty good, but nothing amazing.  However, the true value this car ended up offering was its role as a learning instrument.  It completely changed the way I drive and has helped my fuel efficiency and gas savings to sky rocket!  In hopes of sharing what I have learned, I am writing this post to try and inspire others to follow a similar path and learn how interesting and rewarding efficient driving can be.

     By upgrading to 2015 hybrid technology, the newest and most effective tool at my disposal was the mpg display.  This display both gave me an average mpg over a chosen distance AND an instantaneous display of how much gas was being used at the moment.  As monumental as the first speedometer or tachometer, this display grants the driver a deeper awareness into what this complex machine is doing behind the scenes.  It also encouraged me to try and get as good at saving gas as I possibly could, enabling various efficiency-increasing methods to be attempted and then measured either in real-time or over a set distance.  When I first bought the car, I was averaging roughly the same efficiency as the EPA rating for the car: 33/38 mpg in the city/on the highway.  Then, after a couple months of testing various techniques, I was consistently able to produce an average of 42 mpg city and 53 mpg on the highway…. WOW!  Busting out the ol’ calculator, that is an efficiency increase of over 30%!  I did not modify the car at all, just my own driving habits. 

     Now, I apply this understanding to every vehicle I drive, both lowering my carbon emissions and saving money simultaneously: WIN WIN.  To put this driving mentality concisely: maintain momentum.  Momentum is at the heart of engine efficiency.  Engines are most efficient when maintaining the momentum of your vehicle at an unchanging speed.  Increasing the speed and adding momentum to a car is the least efficient and where the most gas gets used.  Below are eight “Means of Efficiency”, in-depth, yet concise, with extra detail on maintaining momentum:

1)      ACCELERATE SLOWLY: Watch your engine speed (rpm) on the tachometer and try to accelerate slowly, keeping your shifting within the low end of the middle rpm range, around 2,000 to 3,000 rpm. Mid-range engine speeds are where the engine gets the most acceleration for the least gas.  When the engine is at a low speed there are efficiency losses due to friction.  When the engine is at high speed efficiency decreases due to heat.

2)      BRAKE RARELY:  Braking is the enemy of efficiency.  According to Sir Isaac Newton, “an object in motion stay in motion” and requires energy to change speed.  All the energy we put into getting our cars up and going is wasted when we slow ourselves back down.  Then more energy needs to be applied to get the car back up to speed.  Luckily hybrids and electric vehicles can capture some of that barking energy through regenerative braking.  This is where an electric generator creates electricity using the wheels’ momentum, storing that electricity on the battery while helping to slow the vehicle down.  Most cars on the road are not hybrids or electric vehicles (yet), and braking should be avoided as often as possible, without sacrificing safety of course!

3)      BRAKE EARLY: When you do need to slow down, start braking early.  Most events we slow down for are only temporary and will often clear-up quickly.  For example, when a light turns green traffic takes time to get moving at first, but after only a few seconds it all gets up to speed.  The longer it takes for you to get to that traffic, the better chance you have of coasting right through with it.  Approaching traffic, you may only need to slow from 35 mph to 30 mph from 100 yards away before it starts moving, as oppose to going from 35 mph to 0 mph if you start braking from 20 feet away.

4)      COAST OFTEN:  Once you get up to speed, do your best to stay there, adding only just enough gas to keep you going, and letting off the gas to slow down as needed, without touching the brakes.  Gently is the key word.

5)      USE HILLS:  Hills are simultaneously amazing and horrible.  While climbing hills will require a lot of speed, potential energy is being built up in your vehicle the whole ride up.  Coming down the other side will unleash that stored energy and get you back up to a high speed.  Driving west from Albuquerque on I-40 is a great example of large hills.  Try to use the least amount of energy to get up a hill, slowing down as you do so, just like a semi-truck.  Then use the downhill slope to go as fast as you safely can, regaining the energy you stored in getting up the hill.

6)      WATCH TRAFFIC:  It is a good practice to constantly be aware of what traffic is doing around you.  There may be someone turning several cars ahead of you, who has not yet slowed you down, but likely will soon.  If you are aware of this event from a distance, you can changes lanes to avoid having to stop at all, or maybe start braking early in hopes of arriving once the event is already over.  Another example is when brake lights are visible far ahead of you, maybe when you are on the freeway.  Seeing this could again allow you to brake early and arrive after the event.  Maybe it helps you to change lanes to avoid an accident or decide to take an early exit to avoid gridlock traffic.

7)      WORK WITH TRAFFIC LIGHTS:  Many traffic light systems are set up to get traffic through as efficiently as possible.  Most of them use timers that are programmed to turn green just before the next wave of traffic arrives.  These timers are usually programmed around an average car driving the speed limit.  If you drive the speed limit between timed lights you will theoretically get all greens while you are one the same street.  Some streets are programmed slightly differently than others, so you may need to go slightly slower or faster than the speed limit depending on the street.  Once you learn a street’s system it will always work.  Timed streets I use regularly are Montgomery, Wyoming, Lead, and Coal.  If you can get with the flow of traffic on these lights, and generally stay the speed limit, they will often allow smooth and steady travel.

8)      GREEN INDICATORS:  As you approach a red light there are some indicators for when it will switch to green.  A common one to watch for is what the oncoming traffic is doing.  If it is starting to move through the light, your side will likely get the green soon.  Oncoming, left-turning vehicles are the most common reason one side will start moving before the others.  The number of oncoming left-turners will usually determine how long until the green.  Look for left-turners in this scenario and know if there are many, your light will take longer to change.  Another indicator is surprisingly simpler.  Sometimes perpendicular traffic lights are visible as you approach an intersection.  Seeing them turn yellow and then red is a sure way to tell if your light is about to change to green.  If you are braking for your light early, then see a yellow on the opposing light, you can slowly begin a coast toward the light, and hopefully keep our momentum up by the time it turns green.

     Each of these methods can be optimized and added to, but these are the basic ideas I have found success using.  If anyone reading this has anything to add, has questions, or just wants to geek-out about the joy and reward of efficient driving, feel free to contact me here at Vibrantcy!

Trevor Keegan

trevor@vibrantcy.org