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Most efficient route to work

Discussion in 'Gen 2 Prius Fuel Economy' started by LaughingBonsai, Dec 16, 2011.

  1. LaughingBonsai

    LaughingBonsai New Member

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    For all of you commuters out there, have any of you determined the most efficient route for driving to work? If so, what was your procedure?


    I have a ~20 mile (each way) commute to work and I'm going to start logging my MPG for the various routes I take (including some new ones!). My plan is to travel each route consistently (both ways) for a work-week, starting the week with my MFD mpg readout at 0 (I don't have a ScanGauge yet, otherwise I would use it as a cross-check). At the end of the work-week, I will log my final MPG for that route and begin the next route the following week. Obviously, this isn't the ideal time for doing this kind of test in New England (since the temperature will be dropping) so I may need to repeat in the spring.


    I'm hoping that the most efficient route will yield at least a little less gas consumption by driving it consistently through the year. Even if I only see a small increase in efficiency, it will be a fun experiment :)
    I've attached a couple of PDFs that I created from Google Earth (for reference) with the elevation profile of each route as well as some basic route information.


    Any bets on which route will yield the best mpg? If I change the home-bound route, which do you think will be more efficient? Also looking for comments on the procedure.
     

    Attached Files:

  2. rcf@eventide.com

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    This is a very interesting and worthwhile experiment. Theoretically, the gravitational field is conservative and so intermediate elevation changes don't matter. If you believe that for driving, though, I have this bridge for sale...

    I have only two practical routes to/from work. The longer route, 31 miles, has fewer traffic lights but less consistent elevation changes. The shorter route, 30 miles, is almost all uphill or downhill, but has a number of unpredictable traffic lights. Because of that and, as you point out, temperature and other seasonal variables, I think it would take a lot more than a week or two of each route to get accurate results, especially since the difference is likely to be small. Even so, it would be good to know such things, so thanks for volunteering!

    Richard
     
  3. LaughingBonsai

    LaughingBonsai New Member

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    Hmm, good point. If you looked at the PDF, you'll see that one of the routes has 11 stop lights which can add a lot of variance day-by-day. I may need to extend it to closer to a month per route to get a more accurate result. Maybe I'll wait for spring to start the official experiment, when temperatures are more consistent. If we have anything close to the winter we had last year (snow, then mild temp, then snow, some more snow, then more mild temps) the data will be completely invalid :-P

    Anyone else have suggestions regarding the amount of time per route?
     
  4. richard schumacher

    richard schumacher shortbus driver

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    Serious fuel-economy types collect data for a full year before drawing conclusions. There are any number of cases on the site of people who fool themselves badly by considering only one tank or one month's worth of driving. External variables over which you have no control, mostly the temperature and wind, have very large effects. And people often forget to check the tire pressures often enough. For a good test you would need to do it every day and keep them constant.

    Just checking, now: you do mean "fuel economy" and not "MPGs", right? Consider a 100 mile drive at 50 MPG and a 10 mile drive at 20 MPGs. The longer drive has better MPGs but the shorter drive has better fuel economy (it uses less fuel).
     
  5. LaughingBonsai

    LaughingBonsai New Member

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    Richard,

    You are correct, I should have elaborated. I am curious about which route has the best MPG with each route varying in terrain and number of stops. More importantly though, I'm concerned with which route provides the best fuel economy (least amount of fuel consumed to get me from Point A to Point B).

    1 year seems like an awfully long time to collect data from each route, but you're probably right. With the number of variables, the experiment would need to be performed throughout a full year, through all seasons, for each route to provide an absolutely accurate conclusion.
     
  6. JimN

    JimN Let the games begin!

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    Numbers shouldn't be the only criteria. Elapsed time, stree & traffic are also important. I switched from highway to county road because there is much less traffic, mostly just a slightly lower posted speed limit, and it's just more fun to drive.

    It probably won't take long for you to figure out what is best for you. Drive them all. Make all familiar.

    Either way, knowing alternate routes can save hours of being stuck in traffic and you don't want to find one in the pouring rain at night after a full day at the office.
     
  7. ItsNotAboutTheMoney

    ItsNotAboutTheMoney EditProfOptInfoCustomUser Title

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    Without having more details I think the 17.8 mile (route 4) for traveling to work:
    - Short
    - Few stops and lights
    - After the initial climb is mostly a gradual downhill. Prius loves a gradual descent.

    However, it does have the big climb only 1 mile into the route which could work your cold engine hard.

    Route 2, with its reduced elevation changes might be better, especially for the return leg, since it would have a downhill start, which is great during warm-up. There are lots of lights though, so I guess it depends on whether you can time or smart-brake your way through.

    However, as others mentioned different routes have different stress levels. There are different road conditions and all stops are not created equal: there's a big difference between an easy right onto a lightly-traveled back road and a left turn close to a blind corner onto a busy high-speed road.
     
  8. LaughingBonsai

    LaughingBonsai New Member

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    Noted: Will also time the trips and make note of traffic as well as which lights I get stuck at. I drove Route 5 the other day for the first time, great drive. Windy roads, gradual terrain, but a lot of stop signs. BUT, as you said, good to know the route. When the hurricane came through this summer, there was one way out of town for a week and a lot of roads in other towns were impassable.

    PS- GREAT avatar! I will never ever ever justify buying one, but it sure is nice to look at :-P

    I travel Route 4 pretty often and that big hill is one of the reasons I decided to test my options. After making the elevation profiles, I realized that I could avoid some of the elevation gain but with tradeoffs.

    I tried Route 2 last week and there were lots of stops, but it was less stressful than I thought it would be. Something I need to keep in mind: arriving a few minutes late/early at some of these lights makes a HUGE difference in traffic.
     
  9. kornkob

    kornkob New Member

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    I've noticed that in my neighborhood, there are times of day, particularly in the morning where daily traffic is dramatically different with just a few minutes difference. If I reach the major road 2 miles away from home at 645am, I'm first in line at the light. If I'm there are 650, I'm WAY in back. Closer to 7am and it clears up again.
     
  10. Corwyn

    Corwyn Energy Curmudgeon

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    Instead of driving each one for a week, how about each one once a week. That way you will approach an answer rather than waiting 5 weeks for one.