Posted by: Transform Limiting Beliefs | July 19, 2012

The Prius Effect: Changing Behavior in Real Time

EDA Co-Founder Ina Pockrass shares how real-time feedback can drive behavior change

Some may think it a recipe for marital discord that my husband and I share one car, our beloved “Polly” the Prius, but the real shocker is how that car has changed the way we both drive.

If you haven’t seen the Prius dashboard, it looks like something from the Jetsons: all LED lights and flashing graphics, letting the driver know when the engine is running on silent battery power and when it’s drawing on the gas engine.  It also includes a lighted gauge which tells the driver, in real time, how many miles per gallon the car is getting. Step hard on the gas to pass a truck, and the MPG plummets under 10, ease up on the gas, and the gauge climbs all the way to 100 MPG, and beyond.  100 MPG!! For over achievers like us, it’s exciting to see how we can control fuel consumption to get the most out of every drop of “dino fuel” and to keep that gauge as close to 100 MPG as possible.

The funny thing is that having this one little piece of real-time feedback has actually changed our driving habits.  We’ve traded in our lead-footed ways, for the easy-footed satisfaction of keeping the engine using battery power as long as possible.  Instead of revving the engine at a stoplight in preparation to pass the little old lady in the Cadillac in the next lane, we gently accelerate past her, smugly smiling as we watch the MPG gauge climb toward the sky.

We are not alone in loving this real-time feedback and we are not alone in the way having this real-time feedback has changed our behavior.  Scientists are studying the so-called “Prius effect” and incorporating real time feedback mechanisms into everything from consumer electronics to manufacturing facilities.  The point here is that knowledge is power, and when we’re informed about the direct impact of our behavior, like knowing that having a lead-foot on the gas pedal reduces our MPG by as much as 90%, we have put the power in our own hands to change the way we act, now.

Here’s hoping we see a continued rise in on-the-spot feedback mechanisms in other areas of our lives, accelerating our efforts to steward our over-burdened planet.


  1. Indeed! With real-time feedback, consuming less fuel becomes a game. The good news is that most newer cars (1996+) can use something called a ScanGauge. It gives digital readouts of all your standard gauges and presents all sorts of fuel economy data, including an instantaneous readout. I’ve had one on my car for 2 years and it has really helped me track my mileage. I was getting 28-33 cty/hwy before. Now I get 33 on average with mixed driving (occasionally reaching 36-39 per tank on good days/roads/traffic conditions).

  2. […] has already been incorporated into many newer cars like the Honda Civic and the Toyota Prius–The Prius Effect).  I recommend the ScanGauge, which is compatible with most vehicles 1996 and newer with OBDII […]

  3. The Hybrid System Indicator (HSI) is a better guide to driving style and can really help reduce fuel use. Switch the HUD to display the HSI too. The small analogue style MPG gauge (or L/100km in my case) is not the best way to judge driving style.

    Broadly speaking, the left half of the HSI is electric and the right half is petrol (gas).
    The best acceleration v. economy point is about 2/3 into the petrol section. This will also charge the HV battery.
    The best braking point is within the CHG range without filling it. That maximises regenerative braking without touching the brake discs. (And the B setting spins the engine, so it is not as good as using the brake pedal. Only use B if the hill is long and steep and the HV is already full.)
    In general, I stay below the PWR section, but don’t feel bad if you must go into that zone.
    You can balance the accelerator to reach a point between CHG and electric and glide the car.

    Having said that, the HSI economy reading can be a bit generous; mine is 6.5% optimistic. It might read 4.4l/100km but is really 4.7l/100km when I fill the tank..

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