Commute Fuel-Economy Evaluation

[Natalya]

On my way to work I have to make it from the top left corner heading East on Pine Grove Road to the bottom right corner on Atlanta Street. My commute doesn't start or end there, this is just a case of different routes I can choose for this part of the drive. I want to choose the route which results in me burning the smallest volume of gas.

On the plus side: There's usually no traffic as I work at funny times, so I don't deal with rush hour.

As Google Maps shows, the top route is the shortest, the middle route is probably the fastest, and the bottom route is the longest.

█ This pinkish colour is elevation in feet. █

However, there are some traffic lights and elevation changes which makes this commute a difficult decision. On my map I drew in traffic lights. Red means I almost always need to stop, green means I almost always get to go, and yellow means it's a tossup. I'm driving the Insight which does have working Auto-Stop, so the lights aren't terrible, but the stop and go means decel then accel again.

Right now I almost exclusively take the bottom route because of elevation. As you can see, once I get down the hill it's mostly flat until a slight rise at the end. However, you can also see that I have to stop more frequently on this route, and it's half a mile longer.

I kinda doubt the route Google gives is the best route because you have to stop at the bottom of a big hill and then climb back up the other hill and stop once again. But the top route might be a contender because it is shorter and I'll usually only have to stop once up in the top right corner.

What do y'all think are the most important factors here?

[Fat Charlie]

"Stop every time" sounds bad, but it's predictable. I love predictable. To me, the bottom route feels best but middle might actually be better. Only way is to note fuel remaining at the start and finish of the three, and do each a few times.

[Natalya]

I could do all three in a row and the fuel gauge might not change even 1 bar. Is there maybe some kind of sensor or something that tells you the exact volume of fuel in the tank?

Originally Posted by Old Tele man

I'd pick the route having the least change in elevations, ie: the most "level" route.

Yeah that's my initial guess as well. The top route I have to climb twice for a total of about +150 feet, but I only need to stop one time and it's a half-mile shorter than the bottom, flatter route where I stop 4 times, so that's why I'm not sure.

[elhigh]

I'd choose the one that had the fewest stops. With care you can bank a little extra speed before hitting the hills, or spend more of the downhill gliding, maybe even engine off.

[bentring]

With those choices I'd probably just go whichever way I enjoyed driving through the best. Having to pick I'd say go the shortest route both ways. I'd be tempted to say go home the longest because of the long flat while the car is coldest, but it has the most stops and it's all uphill so I dunno if it's worth it.

[Natalya]

Oh the home commute is substantially different. Because of yields and stuff I'd have to make a different diagram with new information about the lights. Sometimes I don't even go home this way because 2-3 times a week I go to other stuff in the evening anyway and end up on a different side of town.

And each direction the car is already warm by the time I enter this portion of the commute, like I mentioned in OP the commute doesn't start at the top left and end bottom right, those are just where these three possible routes converge.

[oldtamiyaphile]

Originally Posted by Old Tele man

Then AVERAGE all the MPG numbers for EACH individual path...then use the path yielding your best 'measure' MPG.

Except what you should actually log is TFC - total fuel consumption (cost).

I set my SG fuel price to $1 so TFC is consumption rather than cost.

[Fat Charlie]

Originally Posted by Natalya

I could do all three in a row and the fuel gauge might not change even 1 bar. Is there maybe some kind of sensor or something that tells you the exact volume of fuel in the tank?

Yes. You need a ScanGauge or an UltraGauge. The UG is way cheaper, but the SG can apparently do more. "Fuel remaining" is much more useful than a needle, a bar, or DTE.

[justy999cc]

In Victoria BC there are enough hills that I sort of plan the best up that connects to the best down. like I lived on top of a hill and my start was great, but then you plan for lack of climb or weight out weather or not you have a distance vs climb. now that I'm in a smaller car (Mercedes 300D turbo rwd boat Vs Subaru Justy 2wd carb) it doesn't weight much and it's got much lower gearing. Does not climb like my 83 Rabbit ever did however, it's way way better on dirt roads.