Energy Wasted By Average Driver

Cannot supply what you wanted, but a useful analogy is to refer folks to 35 mph crash tests. The utter destruction of those cars is the energy thrown away using friction brakes.

 

That all depends on the weight, efficiency, and speed of the car. The kinetic energy in the car is 1/2mv*v. If they slam on the brakes, most of this energy is used to create heat. Anouther way to look at it is supplying this energy is an inefficient engine, so we can divide by engine efficiency to speed add this energy to the car. I also don't know the amount of power in a washing machine, but the energy used is fairly straight forward physics.

For a car around the weight of the camry I would think the energy wasted would be about
energy = 2000 kg * ((speedFast x speedFast) - (speedSlow x speedSlow))

The prius would be a lower number because of more efficient engine to accelerate and recaptured energy in braking.

 

As already stated, there are many variables, so it is difficult to quantify.
An example of brake wear may work just as well. People who tend to speed up to stoplights and then slam on the brakes will need to replace their brakes far more often. I have heard of Prius drivers who didn't need to replace their brakes for 100,000 miles.

 

I could but I won't, too many people are already convinced that Prius owners are a bunch of self-righteous twits. No need to add to that.

 

Let's just do it the simple way; assume average car gets 25 MPG and could get 27 MPG if they drove more carefully. Lets assume 15000 miles per year. So we get 44.4 gaso gals per year wasted, assuming the guy is not in a Prius.

Now if we want to play How to Lie with Statistics, the US EPA uses a value of 33.7 Kwhr per gallon of gasoline. That gives us about 1500 Kwhr wasted elec. According to Google, a washing machine uses 0.25 kwhr per load, so thats 6000 loads of wash!

What's wrong here is that power plants average closer to 30-40% efficent so 6000/3 = 2000 loads, still impressive!

 

OTOH, why do you want to convince them that it would be more efficient to run the red light?

 

Pls note I added to the orig post

 

Putting a scan gauge in my Subaru, and driving carefully, allows me to get ~10% better mileage, but I drive pretty conservatively anyway. I think for the average daily urban driver might save 15% if they learned how to drive. That translates to over $.50/gal at today's prices.

People piss an moan about a few cents a gallon, but don't realize they could save way more if they just drove more efficiently. Move from the Subaru to the Prius, and it translates to nearly a$2/gallon effective fuel price savings!

Icarus

 

Throw that $600 idea at them and let them chew on it a while. Maybe they'll be interested, maybe they won't.

No need to beat them over the head with it, though. Born again converts and their preaching are a drag no matter what flag they fly.

 

OK lets say the guy steps on it 1/3-mile @ 10 MPG when he could have coasted.
So the net loss is .033 gal x $4/gal = 13.2 cents lost could buy 1 kwhr elec to do 4 wash loads instead, assuming 0.25 kwhr per wash load.

 

I get 10mpg in the truck no matter how delicately I drive. There' no improving it, it's the way it is.

If I try real hard I can improve the Camaro from 20 to maybe 21.5

My old CRX varied from 35 to 41.

Not all vehicles are capable. Not all drivers are retrainable.

One persons stupid driver is another persons "maximizing available time." One light challenged and beat is another minute or two gained at the job site or coffee table. Multiply that times wins per year and the hard working landscaper may challenge that $600.

A lot simply depends on the way you look at the world...and oil.

 

The energy to brake, should be roughly the same energy expended to reach top speed ,without interruption ,before braking .

 

You may be missing 10% in the decimal, but I'm not surprised to hear your experience. I bet the truck engine has horrible thermal efficiency when you feather the go pedal.

I think a manual tranny and a clued-in driver could do a lot better with a pulse and coast routine.