Putting My Prius Through the MPG Acid Test

Today i started a training class that will run 5 weeks. the training site is less than a mile away from my home and i just found out that we are breaking one hour for lunch. it will be 5 days a week for 5 weeks.

so with all these short trips, (i will be coming home for lunch most of the time) it will be interesting to see how my mileage will suffer. so i dutifully filled up last night to have a fresh tank to work on.

of course, life goes on so there will be other driving mixed in with the short trips, but so far results are

5.4 @ 38.4 mpg...

now my goal of 55 mpg lifetime will probably be shot down :guns: in flames...

will try to give weekly progress reports as i keep my signature up to date.

 

i dont do rain and i might bike but i dont ride at night and it will be dark when leaving.

 

oh i suspect that my overall mileage will still be around 50 for the tank... the best part of short trips is they are short trips. even a lot of them wouldnt have as great an effect on the tank mileage.

after saying that, i am now at 9.3 miles @ 34.3 mpg...

but that is because i have gone no where else but to work, gym (which is even closer) and home.

but sooner or later, i will have to run errands or make some other trip and im sure my mileage will get a boost to near 50.

at least that is what im predicting... keep in mind that 50 mpg might sound good to some but my last 4 tanks were 55.1, 58.1, 56.1, and 54.5 and i have come to expect 54 mpg minimum at least until they start the winter formula gas which i was told will be happening here shortly.

 

well after the first week update, i had been making all the short trips all week (average trip length 1.1 miles)
my average was 35.7 then i took 3 round trips to sis's house which is 5.5 miles one way and that was enough to raise my tank average to 43.4 mpg.

then i took a trip to seattle which is about 120 miles RT and now im at 51.9 mpg for the tank.

but now its sunday night and tommorrow starts another round of short trips which consists of trip to gym and back, school and back for lunch then school and back again for total of 6 trips a day.

i am encouraged by the significant increase in mpg when the trip was longer. it appears that my big mileage hit only lasts just under 2 miles. so anything beyond that length gets me back to normal. the longer i go, the better i offset the initial poor mileage.

i have been kicking around the idea of figuring an alternate route this week that would make the one way distance 2 miles just to see what the outcome would be.

 

sounds like you are doing a lot of what you need to do.

my tires are at 38/36. could be more i guess and the added air did add 1-2 mpg.

also another thing that many subscribe to and that is accelerating to your target speed quickly.

the theory being that constant velocity uses much less power than accelerating even moderately and the less time spent accelerating the more the mpg will be overall.

this makes sense. even with a very light touch, i will go down to 25-30 mpg on realtime graph. but rapid acceleration will drop me to 10-15 mpg. so the question is what is better?? 30 secs @ 25-30 mpg or 10 sec @ 10-15 mpg.

i do a lot of congested freeway driving too and nearly without exception, this is where my mileage really zooms! but the trick here is cruise control. its very challenging to use cruise control when your speed is running from 25-50 mph. but using cruise control forces you to anticipate traffic better. remember that if you have to stop you are going to fast. sure you may seem like you are going too slow and lots of cars will be cutting in front of you but when you really look at it, you might realize that the car you were behind might only be 10-15 car lengths ahead of you after you get through the slow section. well that is say a ¼ mile that car gained on you with aggresive driving that may have reduced your mileage in that section by as much as 50%. if the section was 10 miles long, you will have lost a total time of 1-2 minutes on the freeway at the most, usually much less than that.

realize the reduction in stress from not being on ones bumper or worrying about someone rear ending you (i know that sounds strange especially when there is little doubt that someone is on yer nice person fuming bigtime, but you will find that he can maintain that close following distance because you are driving in a predictable pattern, thus reducing chances of a collision. its the rabbit speed ups and rapid slowdowns that cause accidents)

im not sure this is true but many swear by it. i tried a test to see what difference if any would be noticeable, but after several days of both types of driving my results were inconclusive.