Total fuel used VS average MPG
 

I started experimenting going back and forth to work, basicly theres the city and highway paths.

Going through the city gets me worst MPG, highway I get higher MPG.

BUT my scangauge tell me I burned more fuel going through highway even though I got better MPG...the highway makes me drive 2 KM more.

I usually burn around 1 litre on highway and 0.8 in city...That sounds counter intuitive as on my MPG record it looks worst but in reality I used less fuel.

..Just a warning that a better MPG doesn't mean you are using the best road..:) ...I just realized alot of hypermilers might get caught in that trap...

Also...0.8 litre of fuel used I guess you guys realized it takes me 10 minutes to get to work..my engine is only warmed up 1/3 of the way there..I think its why my MPG isn't that high for my small 2.0 engine :/

Great point. After all this is "Gas Savers" and not "MPG improvers"...

One other thing to consider however. Frequently city driving involves bumpier roads with more stop-and-go, these wear out brakes, shocks, clutches, and other parts more quickly than a smoother highway ride. Expensive maintenance items can quickly drive up costs compared to a few saved liters of fuel. It takes a LOT of driving to pay back a $300 set of struts.

-Bob C.

I use less gas taking the more direct route home from work, which has traffic lights every 1/4 mile (strip-mall city), than the alternate route with lights every 3/4 to 1 mile. While the longer route raises my MPG, the gallons used is higher. 7 miles @0.12 gallons vs 8 miles @0.14 gallons. I should time the routes with my phone's stopwatch to see if I'm also saving time with the shorter wait-at-lights route.

I primarily take the longer route to work in the morning as my "slow" driving aggravates others less and I am more relaxed en route.

I must admit, in running my daily errands I take a longer route on my return trip because of how the signal lights are timed at that time of day. It seems that its easy to get out, but to get back you end up stopping every 100 yards for a traffic light. I take a slightly longer route through a residential neighborhood where the speed limit is 35, but I only encounter 3 lights on the way back, and 2 of them I can make a Right on Red so they really don't even count. I'm not waiting for the signal to turn. I never figured out which route actually used less gas, but the neighborhood street definately yields better MPG (and is quicker).

-Jay

If I take the city route where I go, with all the traffic lights, stop signs, traffic, and 30 mph speed limit, it takes me about 15 minutes longer. This is constant stop and go and never getting into o/d which is my most fuel efficient gear. There are just too many stops and starts to count. Not to mention the additional mechanical wear and tear.

If I take the highway, which is approximately 1 and 1/2 miles longer, but I am cruising in o/d which is my most fuel efficient gear, and eliminating all the stop and go, and extra wear and tear, and I get there 15 minutes faster so the motor gets shut down 15 minutes sooner. The motor does not use any gas for that 15 minutes.

I never tried to calculate exactly how much fuel is used under each scanerio, but my scan gague reads awful low numbers acelerating from stop to 20-30 mph over and over again.

Just my experience.

Your scangauge tell you the gas usage...try both ways and there still good chance you have lower usage in town...like me!

Excellent point. I have noticed that myself. I do my testing with the cost function of the scanguage. Even with gas in the low $2 range, I want to spend as little as possible at the pump.

I discovered a really cheap and accurate way to figure gas mileage.
You 'new math' types may not know how, but old timers use a little arithmetic and calculate it.

Seriously, the only figures that matter are 'average' MPG, over the longest possible period. That removes the problems caused by gas pumps that shut off too soon, filling on a slight slope, getting caught for an hour in the 'commute crawl' and just getting fed-up and stomping on it every now and then.
Nite-nite.

That's great for determining the effect of a modification or driving technique over the long term, but it can't tell you which route uses less gas.

I think that's the purpose of the 90 day average...