[jdr]

I tried hypermiling on my 2002 Hyundai accent 1.5 petrol in Pune a little while back. I didn't know it was called hypermiling at the time.

Here's what I did:
1. I accelerated gently to required speed. Obtaining required speed is all guesswork; depending on traffic and grade and quality of road, etc.
2. After getting up to speed, I put the car in neutral (or sometimes in high gear just press the clutch (rarely, if I feel that I might need to quickly engage the engine)) and coast till speed drops to around 25-30kmph.
3. Repeat
4. All of the above was done with utmost concentration upon driving and watching the road. This is Pune after all, and you have all sorts of animals crossing the streets (including humans and other vehicles :P)

Here's what I didn't do:
1. I didn't switch off the engine everytime.
2. I didn't stick behind any other vehicle (not sure what it's called (tail gating?))

Gains:
1. Mileage went up from 11 to 14 (tried only once with one tank of gas)
2. With more practice, gains might go up to 15 (all city driving)

Observations:
1. The effort required to drive safely with the technique is not worth the gains in mileage
2. I won't be doing it again (did it once just for the sake of experimentation)
3. If mileage is your main concern, get a better mileage car or convert to cng

Jdr

[apachelongbow]

How about this? In the Safari, just not touching the accelerator (leaving the engine to idle), and changing gears, one can reach upto 50kmph in the 5th gear, now imagine driving like this all the time, I am sure the Safari will give upwards of 20kmpl!!!!
Note: The ECU compensates for slopes, speed brakers etc by increasing idling rpm to prevent an engine stall.

[sarathlal]

Slightly off topic, For Americans, more than the exorbitant nature, aren't they left without choice other than to stick to heavier and powerful cars?

Most of the freeways run through vast open space, where cross winds are extremely high. Small cars will be extremely difficult to control on such roads.
They opt for heavier and powerful cars for the sake of safety and the capacity to pull through extreme weather conditions, which includes high winds, sporadic hurricanes, extreme snow etc.

Nowadays, cars like Jazz, Beat etc are gaining entry into the US market, but they mostly are safe only as City cars.

[Rahul Rao]

I think that American cars are in efficient due to wrong choice of engine and gerbox options. My uncle had a Scoda octavia that returned upto 23 inspite of the size and weight, my much smaller Polo rarely does that. Driven with a light foot a BMW 520d returns 14 to 15 kmpl, but the smallest engine the 5 series is sold in the US is a 3 Lit.
Same is the case with almost all vehicles. Other than that the americans prefer a torqueconvertor autobox unlike manual or now DSG's preferred in Europe.

@ apachelongbow
Going from 1st 2 second without touching the accelerator is fine, but beyond that you should accelerate very lightly. I engage 5th at 50kph in my Polo, and the gear recommendation shows (5dot) but even a slight drop shows 4and a down arrow.