Estimating/Modeling Hybrid MPG from EPA numbers - GreenHybrid

doasc · #1 (**permalink**) 05-07-2008, 08:38 PM

Has anyone modeled the MPG of their hybrid versus the same routine driving with a non-hybrid? And in doing so correlate the numbers for both vehicles to their respective EPA ratings?

During the past many years, vehicles, etc. I have been able to closely model/estimate the MPG observed from the % city/highway driving and the EPA numbers. Obviously, certain factors will have short term influence but the long term averages are spot on.

Since a hybrid by design will get better city gas mileage than a non-hybrid. I was curious to see how well they correlate.

bwilson4web · #2 (**permalink**) 05-08-2008, 05:57 PM

Like this:

Bob Wilson

gpsman1 · #3 (**permalink**) 05-09-2008, 12:52 PM

Bob- based on the two routes, I would guestimate your time is worth about $6 an hour.

gumby · #4 (**permalink**) 05-09-2008, 11:00 PM

Quote:

Originally Posted by gpsman1

Bob- based on the two routes, I would guestimate your time is worth about $6 an hour.

I got twice that (nearly $12 an hour), at current gas prices

Gallons of Gas Saved per week = 4.05 - 2.29 = 1.76 gallons
Money Saved per week = 1.76 gallons x $3.60 a gallon = $6.34

Extra Time per week = 5 days x (21:56 - 15:30) = 32.167 minutes.

$6.34 saved per week / 32.167 minutes extra time per week =
$0.197 per minute = $11.82 an hour.

Not so sure that's exactly a raise for an engineer, but it's not bad for Bob's own (potentially) free time.

Now the REAL question is how much worse would Bob's mileage be if he drove the Prius on the same route as the Echo (3 more miles each day), with the same speeds (faster, so presumably less MPG), and compare using THOSE numbers. I suspect that comparison might show a much less hourly rate for Bob's time! (It might be less than $6 an hour, even.)

Or Bob could take his 10-mile Prius route, and just drive that 35 miles per hour leg faster (51 miles per hour?). and maybe on the freeway (to avoid 2 lights), which would minimize the time difference, yet he'd still get significantly better MPG than in the Echo. This could boost his hourly rate.
I'm sick, I know...

gumby · #5 (**permalink**) 05-09-2008, 11:01 PM

Quote:

Originally Posted by gpsman1

Bob- based on the two routes, I would guestimate your time is worth about $6 an hour.

But, I got twice that (nearly $12 an hour), at current gas prices

Gallons of Gas Saved per week = 4.05 - 2.29 = 1.76 gallons
Money Saved per week = 1.76 gallons x $3.60 a gallon = $6.34

Extra Time per week = 5 days x (21:56 - 15:30) = 32.167 minutes.

$6.34 saved per week / 32.167 minutes extra time per week =
$0.197 per minute = $11.82 an hour.

Not so sure that's exactly a raise for an engineer, but it's not bad for Bob's own (potentially) free time.

Now the REAL question is how much worse would Bob's mileage be if he drove the Prius on the same route as the Echo (3 more miles each day), with the same speeds (faster, so presumably less MPG), and compare using THOSE numbers. I suspect that comparison might show a much less hourly rate for Bob's time! (It might be less than $6 an hour, then.)

Or Bob could take his 10-mile Prius route, and just drive that 35 miles per hour leg faster (51 miles per hour?). and maybe on the freeway (to avoid 2 lights), which would minimize the time difference, yet he'd still get significantly better MPG than in the Echo. This could boost his hourly rate.
I'm sick, I know...

doasc · #6 (**permalink**) 05-12-2008, 09:00 AM

Quote:

Originally Posted by gumby

Now the REAL question is how much worse would Bob's mileage be if he drove the Prius on the same route as the Echo (3 more miles each day), with the same speeds (faster, so presumably less MPG), and compare using THOSE numbers. I suspect that comparison might show a much less hourly rate for Bob's time! (It might be less than $6 an hour, even.)

Or Bob could take his 10-mile Prius route, and just drive that 35 miles per hour leg faster (51 miles per hour?). and maybe on the freeway (to avoid 2 lights), which would minimize the time difference, yet he'd still get significantly better MPG than in the Echo. This could boost his hourly rate.
I'm sick, I know...

This is more of what I was thinking of, in terms of the same route with non & hy cars. Since the % highway/city can be assessed from Bob's information. It would be interesting to take the EPA (2008 & pre-2008) and use that information to model the observed MPG. I think there is a "fudge" factor needed to model the relationship and I suspect it will be different for the non & hyb. Hopefully with the model, we could take EPA info for a Hummer, Hybrid Altima, Diesel Jetta, etc and get a fairly accurate estimate of expected MPG on Bob's route.

The concept of modeling is based a lot on my experience with 10 different non-hyb cars over the past 15 years that I drove the same routes, work 46 mile RT and vacation 312 mile RT. I always observed mpg that mapped well to the cars EPA numbers and the characteristics of the route. However, I have no hands on hybrid info... yet

bwilson4web · #7 (**permalink**) 05-12-2008, 10:37 AM

Quote:

Originally Posted by gumby

But, I got twice that (nearly $12 an hour), at current gas prices

Gallons of Gas Saved per week = 4.05 - 2.29 = 1.76 gallons
Money Saved per week = 1.76 gallons x $3.60 a gallon = $6.34

Extra Time per week = 5 days x (21:56 - 15:30) = 32.167 minutes.

$6.34 saved per week / 32.167 minutes extra time per week =
$0.197 per minute = $11.82 an hour.

Not so sure that's exactly a raise for an engineer, but it's not bad for Bob's own (potentially) free time.

Now the REAL question is how much worse would Bob's mileage be if he drove the Prius on the same route as the Echo (3 more miles each day), with the same speeds (faster, so presumably less MPG), and compare using THOSE numbers. I suspect that comparison might show a much less hourly rate for Bob's time! (It might be less than $6 an hour, then.)

Or Bob could take his 10-mile Prius route, and just drive that 35 miles per hour leg faster (51 miles per hour?). and maybe on the freeway (to avoid 2 lights), which would minimize the time difference, yet he'd still get significantly better MPG than in the Echo. This could boost his hourly rate.
I'm sick, I know...

Actually I'm not paid for my commuting time. Since I have XM radio, I have come to enjoy the morning and evening programs on my drive home and have even sat in the driveway or parking lot to hear the end of a report or some tunes. There is also the 'less stress' aspect of slower speeds.

Often I will work over problems at work on the way in or home. Occasionally I'll have a flash of insight ... but I've learned to 'e-mail' these insights from home instead of turning around. For me it has become a quality of life issue secure in the knowledge that entropy did not win so much today. I arrive at work or home relaxed after enjoying the quiet of electric power and avoiding the inevitable jams from accidents by taking a route "less traveled."

Quote:

...

I shall be telling this with a sigh
Somewhere ages and ages hence:
Two roads diverged in a wood, and I--
I took the one less traveled by,
And that has made all the difference

...Robert Frost

Bob Wilson
ps. Not a Type A personality.

gumby · #8 (**permalink**) 05-12-2008, 11:16 PM

Quote:

Originally Posted by bwilson4web

... I have come to enjoy the morning and evening programs on my drive home and have even sat in the driveway or parking lot to hear the end of a report or some tunes. There is also the 'less stress' aspect of slower speeds.

Me too (even without XM...).