You might also see this referred to as 'stop shutdown', 'stop light shutdown', or 'SLSD'.  Most of us have seen a version of this technique... when you are at a railroad crossing and you can see that the train will be passing for several minutes many people will turn their car off.  Hypermilers do this at traffic signals and moreover they will often turn the car off before reaching the light so as to coast before reaching a halt.

About.com has this to say about it:

The Forced Auto Stop (FAS)

The first technique I learned and tried is Forced Auto Stop (FAS), but executing a FAS in a regular car takes a soul braver than I. This task involves coasting down a hill with the car in neutral and the engine shut off. What? Too difficult to control, and WAY too dangerous for my taste—with the engine off, the power brakes and steering are compromised and the steering wheel could lock. No Way! I've tried a similar trick that involves only putting the car in neutral to coast, but leaves the engine on. This method at least keeps the power steering and brakes fully functional, yet allows a slight increase in fuel mileage since the engine is only idling at 700 RPMs instead of perhaps rolling at 2500 RPMs.

The trick, and in my opinion, the Achilles heel of a FAS, is putting the car back into gear to resume acceleration. I've learned that I need to do a rev match (accelerate the idling engine to match the freewheeling transmission speed) so the tranny gears and clutches don't detonate when the slow rotating engine and fast turning tranny re-engage. Just as important though, maybe more so, a proper rev match keeps the drive wheels from momentarily locking up at the moment of re-engagement; loss of control on a slippery road is a real possibility. I think these concerns are slightly moderated with a manual transmission and clutch, but only slightly. I also wonder how this might affect internal transmission lubrication (at least in automatics), and further, how a continuously variable transmission (CVT) would react to repeated engagement and disengagements. Personally, I don't think it's worth damaging a very expensive component for questionable return. I've heard stories of folks using this technique for years with no problems, and that may be, but at best it's a roll of the dice.

eHow:

The forced-auto stop is when you turn off your car and coast. In hybrids, the internal combustion engine shuts off at stops to conserve fuel; the electric batteries keep the car running. To save even more fuel when decelerating, some hypermilers shift to neutral and turn off the engine while coasting to a stop.

Expert's say that this is highly dangerous.

WikiCars:

Stop shutdown

(Transmission mode in B, speed zero)

Often you will pull up at a stop light that has just changed. In some suburban areas this may entail a wait of several minutes, as the lights cycle through various simultaneous or sequential left turns, cross traffic, pedestrians, etc. If the gasoline engine is running when you approached the stop it will take the better part of a minute before the computer recognizes the situation and shuts off the engine. There is a trick to getting the engine to shut off promptly. If you approached the stop in B (engine assist braking), you may then when stopped with the brake on, command D (drive) - the engine will stop immediately - at least in 2004 US versions.

There is a difference of opinion about this technique in the YahooGroup, Prius Technical Stuff. Two senior NHW20 (04-current) Prius owners believe this at most saves 5 seconds of engine run time on the first engine stop event, normally 8 seconds long. The effect does not occur in the NHW11 (01-03) Prius as long as the blue "cold engine" light is on.

The most informative article is at Wikipedia:

Auto-stop, forced stop, and draft-assisted forced stop

In the auto-stop maneuver, the vehicle's transmission is put in neutral, the engine is turned off (a "forced stop"), and the vehicle coasts to a stop. It is possible to coast in neutral with either a manual or automatic transmission. Modern automatic transmissions/transaxles depend on an engine driven fluid pump for lubrication ^[17]and coasting with the engine off may lead to damage or failure of the transmission^[18]. To perform the maneuver, the driver shifts into neutral, and lets the tachometer stabilize, then keys the ignition back to the first position, referred to as "IG-I", to shut off the engine and electronics. The driver then keys forward to IG-II to start the electronics and continue coasting.^[5] The key should remain in the ignition in the IG-II position, and not the IG-I position ^[19], in order to avoid engaging the steering wheel lock.^[20] The driver recovers from "stealth mode" by starting the engine in the normal way, by turning the key to IG-III to crank the starter motor, and then releasing the key back to IG-II. Before putting the transmission in gear, if necessary, the driver may "rev" the engine to match the vehicle's gear and speed. The fuel economy from this advanced technique is increased noticeably over any short distance trip, largely because there are no engine idling losses (see figure below).^[5] Most modern automatics' computer systems do a very good job at keeping the transmission in the proper gear while coasting in neutral, and the driver should not be conscious of the tachometer when re-engaging, but rather just press half-way down on the accelerator when re-engaging.

Some, but not all, hypermilers use this maneuver, and some may use it more safely than others. The technique is used for general coasting, or as part of the pulse-and-glide maneuver, or when going down hills or in other situations when potential energy or momentum will propel the vehicle without engine power.^[1] Some hypermilers may use this maneuver while going downhill, around a corner, and without braking;^[19] however, that practice is in all likelihood more dangerous than an auto-stop on a level and straight road, where stopping distance is shorter and visibility is greater. Vehicle control may be somewhat compromised, and this can be more-or-less dangerous or safe depending on the situation. Turning the engine off will cause the power brake assist to be lost after a few applications of the brake pedal. Power steering is quickly lost, although it is not needed at high speed, only at low speed.^[5] Steering is still possible at low speed, but can often require considerably more arm strength to turn the wheel.

For safety reasons, the maneuver is not recommended for use in traffic, since the driver will want the car to be in gear if sudden acceleration is needed as an evasive maneuver. The driver should first look for traffic behind the vehicle before attempting the maneuver. It can be considered more courteous to not coast if another vehicle is closely following. ^[20] The proper etiquette and acceptable driving practices are controversial, and is worsened by a lack of communication between drivers. Both sides of the debate are often argued passionately, yet sometimes neither of the proposed driving methods is in complete accordance with the rules of the road. Both hypermilers and regular drivers may at different times violate the same rule yet blame the other type of driver.

Despite the potential risks, it does in fact save fuel to turn the engine off instead of idling. Traffic lights are in most cases predictable, and it is often possible to anticipate when a light will turn green. Some traffic lights (in Europe) have timers on them, which assists the driver in using this tactic.^[20]

Draft-assisted forced stop, a variation of the forced (auto)stop (sometimes abbreviated as D-FAS), involves turning off the engine and gliding in neutral while drafting a larger vehicle, in order to take advantage of the reduced wind resistance in its immediate wake (This practice is illegal in some areas due to its danger); while tailgating itself is inherently risky, the danger of collision is increased with D-FAS as hydraulic power for power brakes is used up after a few applications of the brake pedal, and there is a loss of hydraulic pressure that provides power steering, ^[21] however, there is less need for power steering at high speed.^[5]

Some hybrids must keep the engine running whenever the vehicle is in motion and the transmission engaged, although they still have an "auto-stop" feature which engages when the vehicle stops, avoiding waste. Maximizing use of auto-stop on these vehicles is critical because idling causes a severe drop in instantaneous fuel-mileage efficiency to zero miles per gallon, and this lowers the average (or accumulated) fuel-mileage efficiency.

Mini Cooper owners report real world MPG numbers averaging between 25-28 MPG.

The official Mini Cooper website says it will get between 37 MPG city and 28 MPG highway.

It does this with the following setup:

The 2008 Mini Cooper and Mini Cooper Convertible models are fitted with a 1.6 liter four cylinder engine producing 118 horsepower (HP) and 114 foot pounds of torque. Mini claims a 0-60 time of 8.5 seconds and a 1/4 mile time of 16.6 seconds for the hardtop and 8.9/16.5 for the convertible.

The car retails for between $18,000 and $22,000 base model MSRP for model year 2008.

For more information, here is some of what Wikipedia has to say about the Mini Cooper:

The Mini is a small car that was produced by the British Motor Corporation (BMC) and its successors from 1959 until 2000. The most popular British-made car ever, it was superseded by the New MINI, which was launched in April 2001. The original is considered an icon of the 1960s,^[2][3][4] and its space-saving front-wheel-drive layout (that allowed 80% of the area of the car's floorpan to be used for passengers and luggage) influenced a generation of car-makers.^[5] The vehicle is in some ways considered the British equivalent to its German contemporary, the Volkswagen Beetle, which enjoyed similar popularity in North America.

This distinctive two-door car was designed for BMC by Sir Alec Issigonis.^[6][7] It was manufactured at the Longbridge and Cowley plants in the United Kingdom, the Victoria Park / Zetland British Motor Corporation (Australia) factory in Sydney Australia, and later also in Spain (Authi), Belgium, Chile, Italy, Portugal, South Africa, Uruguay, Venezuela and Yugoslavia. The Mini Mk I had three major UK updates: the Mk II, the Clubman and the Mk III. Within these was a series of variations including an estate car, a pickup truck, a van and the Mini Moke — a jeep-like buggy. The Mini Cooper and Cooper "S" were sportier versions that were successful as rally cars, winning the Monte Carlo Rally three times.

Minis were marketed under the Austin and Morris names until Mini became a marque in its own right in 1969.^[8]

Design and development

Designed as project ADO15 (Austin Drawing Office project number 15), the Mini came about because of a fuel shortage. In 1956, as a result of the Suez Crisis which reduced oil supplies, the United Kingdom saw the re-introduction of petrol rationing. Sales of large cars slumped, and there was a boom in the market for so called Bubble cars, which were mainly German in origin. Leonard Lord, the somewhat autocratic head of BMC, decreed that something had to be done quickly. He laid down some basic design requirements: the car should be contained within a box that measured 10 × 4 × 4 feet (3 × 1.2 × 1.2 m); and the passenger accommodation should occupy six feet (1.8 m) of the 10 foot (3 m) length; and the engine, for reasons of cost, should be an existing unit. Issigonis, who had been working for Alvis, had been recruited back to BMC in 1955 and, with his skills in designing small cars, was a natural for the task. The team that designed the Mini was remarkably small: as well as Issigonis, there was Jack Daniels (who had worked with him on the Morris Minor), Chris Kingham (who had been with him at Alvis), two engineering students and four draughtsmen. Together, by October 1957, they had designed and built the original prototype, which was affectionately named 'The Orange Box' because of its colour.^[2]

The ADO15 used a conventional BMC A-Series four-cylinder water-cooled engine,^[9] but departed from tradition by having it mounted transversely, with the engine-oil-lubricated, four-speed transmission in the sump, and by employing front-wheel drive. Almost all small front-wheel-drive cars developed since have used a similar configuration. The radiator was mounted at the left side of the car so that the engine-mounted fan could be retained, but with reversed pitch so that it blew air into the natural low pressure area under the front wing. This location saved precious vehicle length, but had the disadvantage of feeding the radiator with air that had been heated by passing over the engine.

1959 Morris Mini-Minor interior

The suspension system, designed by Issigonis' friend Dr. Alex Moulton at Moulton Developments Limited, used compact rubber cones instead of conventional springs. This ingenious design shrank the overall size of the suspension, meaning that it could take up less space. It was built into the subframes. The use of the rubber cones led to a rather raw and bumpy ride, but this rigidity, together with the wheels being pushed out to the corners of the car, gave the Mini its famous go kart-like handling. It was initially planned to use an interconnected fluid system — similar to the one which Issigonis and Moulton were working on in the mid-1950s at Alvis — but the short development time of the car meant this was not ready in time for the Mini's launch. The system intended for the Mini was further developed to become the hydrolastic system and was first used on the Austin 1100, launched in 1962. Ten-inch (254 mm) wheels were specified, so new tyres needed to be developed, the initial contract going to Dunlop.

The Mini was designed with sliding windows in the doors, thus allowing for storage pockets to be fitted in the space where a winding window mechanism would have been. Issigonis is said to have sized the resulting storage bins to take a bottle of his favourite Gordon's Gin. The boot lid was designed with the hinges at the bottom so that the car could be driven with it open to increase luggage space. On early cars the number plate was hinged so it swung down to remain visible when the boot lid was open. Although it has to be mentioned that this design was later discontinued as it was discovered that exhaust gasses could leak into the cockpit while the boot was open.

The Mini was designed as a monocoque shell with welded seams that are visible on the outside of the car running down the A and C pillars, and between the body and the floor pan showing where the joins are. To further simplify construction, the car had external door and boot hinges.

This cross-sectioned Mini demonstrates how passenger space is maximised.

All of these novel and elegant technical innovations resulted in a car with minimum overall dimensions yet maximised space for both passengers and luggage.

Production models differed from the prototype by the addition of front and rear subframes to the unibody to take the suspension loads, and by turning the engine around with the carburettor at the back rather than at the front. This required an extra gear to be placed between engine and transmission to reverse the engine direction. Making this a reduction gear had the beneficial effect of reducing loads on the gearbox and preventing the rapid wear on the synchromesh which had been a problem on early prototypes. Having the carburettor at the rear helped to reduce carburettor icing, but did expose the distributor to water coming in through the grille. The engine size was reduced from 948 to 848 cc, which reduced the top speed from an unprecedented 90 mph (145 km/h) to a more manageable (for the time) 72 mph (116 km/h) — a decision that was reversed in 1967.

Despite its utilitarian origins, the classic Mini shape had become so iconic that by the 1990s, Rover Group — the heirs to BMC — were able to register its design as a trade mark in its own right.^[10]

Read the rest from Wikipedia.

Here's what Wayne Gerdes recently had to say about the hypermiler trick of drafting:

Q: What about drafting – following a large vehicle to reduce wind resistance?

A: Drafting is like NASCAR. Don't do that on the road or you'll be dead.

You really can't get much more explicit than that.

Drafting is the most controversial hypermiler trick, and for good reason. People associate drafting with racing and the Venn diagram of hypermiling enthusiasts and racing enthusiasts has a huge overlap. There's a certain romantic notion tied to drafting- it seems like a cool thing to do. The problem is that while the relative coolness of drafting might be argued, the relative danger of it is not up for debate.

When you draft while hypermiling you are in essence putting your safety into the hands of the driver you are behind. I don't know about you, but there aren't very many people out on the roads that I trust with my life.

Saving gas is certainly not worth risking my neck over.

The Baltimore Sun recently summarized the subject this way:

...some auto experts question the safety of advanced hypermiling techniques such as "drafting" - closely following tractor-trailers to cut down on the flow of air against a vehicle.

Leon James, a University of Hawaii professor who has written about the psychology of driving, said hypermiling can become a form of aggressive driving if, for example, drivers practice it in the fast lane, forcing others to drive around them, or if they coast through stop signs.

"If you were behind someone who's practicing certain features of hypermiling, you get very annoyed," James said. "Hypermiling can be a selfish thing to do."

Ed Kriston of AAA said that the automobile group encourages gentle driving to save gas but discourages aggressive types of hypermiling.

"Some of the things they do are very dangerous," he said. He pointed to drivers going below the speed limit on highways such as Interstate 795, where the limit is typically higher than those posted on most highways.

Full story

I shudder to think about the damage that will be done and the bad publicity that will arise after the first incident picked up in the media where people are injured as a result of someone drafting.

Want to look like a hero? Visit one of the ten worst cities on this list and show them your new hypermiling superpowers.  I found this in a story on CNNMoney.

NPR aired a story on Morning Edition on June 9th about hypermiling.  I had saved the link to write about it later and when I told my girlfriend about it she said she had heard it that morning on the radio.  More and more people must be asking "What is hypermiling?" if NPR is covering the phenomenon now.

Here is a highlight from the article,

Adams' hypermilers group installed a miles-per-gallon meter in a reporter's car for a 10-mile test drive. Rather than the 8 miles per gallon the reporter had predicted, he averaged 21.1 mpg. Not only that, but there were periods of coasting with 111 mpg.

You can listen to the story by visiting NPR's website.

Every hypermiler probably has a different technique for pulsing and gliding, but each of them shares at least some methods in common.

First, like this post from last year about the pulse and glide hypermiling technique from MetroMPG.com, we begin with a disclaimer,

Upfront, any discussion of pulse & glide (P&G) almost always includes a disclaimer that goes like this: this is not a "normal" driving technique; it's not particularly easy to do in a non-hybrid; it may cause more wear and tear on the vehicle; and it has the potential to drive fellow motorists crazy (depending on the spread between the min/max speeds of the pulse & glide); it may even be illegal where you live!

BUT... done correctly, in the right conditions, it works.

Alright, so now we have been warned.

Let's review a note from Wikipedia:

Fuel efficiency varies with the vehicle, but generally acceleration is most efficient at near full throttle openings ^[11] It is also important to keep the engine RPM in an efficient range, so acceleration is more fuel-efficient when up-shifting occurs at a lower RPM. Low-RPM up-shifting is easily executed with a manual transmission.

This blog over at Wordpress gives some great first-hand advice on how to use the technique:

Learning how to properly pulse and glide your way to 60+ MPG will take a little patience, a relatively straight, relatively level road where you can safely maintain speeds of 35-40 MPH for long stretches (a road with a lot of stop signs and traffic lights is not ideal), and careful attention to the consumption screen.

The first step, of course, is Pulse. Accelerate up to no more than 41 MPH (the point after which the gas engine will not shut off), using moderate pressure on the accelerator pedal. You should be able to reach 40 in six or seven seconds without “gunning it” (4.9 seconds with maximum throttle according to Motor Trend - but that’s not really good for fuel efficiency).

To glide, lay off the accelerator for a split second before reapplying just enough gentle pressure to get the blue (regenerative breaking) arrows to disappear...

You can accomplish a reasonable facsimile of this process, by the way, in any non-hybrid car with a manual transmission - pulse up to your desired speed, shift into neutral, and turn off the ignition. Do it on the highway, though, and you’ll likely end up dead, having been rear-ended by an 18-wheeler.

And,

This method consists of accelerating to a given speed (the "pulse"), followed by a period of coasting (the "glide"), and then repeating the process. The glide is most efficient when the engine is not running. Because some cars inject extra fuel when the starter is activated, this was originally best accomplished with a manual transmission.^[16] Hybrid vehicles, such as the Toyota Prius, are ideally suited to performing this technique as well: the internal combustion engine, as well as the charging system, can be shut off for the glide by simply manipulating the accelerator.

Lastly, this guide tells us:

Assume you want to average 35mph.

Start at 40mph and allow your vehicle to decelerate, in Neutral, to 30mph -- this is called the glide.

Then, accelerate back up to 40mph in the same amount of time that your glide took -- this is called the pulse.

For the more intense, glide with your engine off. This will increase your FE number dramatically while gliding in gear will reduce them as you'll be combating engine braking.

This technique has been proven many times over to be an effective way to increase mileage. But, your mileage will vary based on traffic and other drivers. Other drivers will get quite pissed off at your pulse and glide, so use your best judgment.

Pulse and glide may be the most important hypermiling technique. It also has the potential to be the most dangerous and so it should only be performed under the right conditions. Use common sense, be courteous to other drivers, and remember that saving some gas is never worth risking anyone's well-being.

Reuters had a pretty good article on hypermiling and hypermiling techniques a few weeks ago.  The article also mentions the nearly omnipresent (at least in hypermiling articles) Wayne Gerdes.  The authors claim that drafting is a popular method used by hypermilers but I think this would be widely disputed.

Known as 'hypermiling,' the method can double gas mileage, even in gas-guzzling vehicles that would normally get less than 20 mpg.

Promoted on a growing number of Web sites, hypermiling includes pumping up tires to the maximum rating on their sidewalls, which may be higher than levels recommended in car manuals; using engine oil of a low viscosity, and the controversial practice of drafting behind other vehicles on the highway to reduce aerodynamic drag -- a practice begun a few years ago by truck drivers.

and,

Deron Lovaas, vehicles campaign director at environmental group the Natural Resources Defense Council, said most hypermiling techniques are "sensible recommendations" that could drive down demand and even prices if widely adopted.

"We should be looking under every rock for potential energy savings," he said.

He said he could not recommend drafting behind fast-moving trucks because it could potentially lead to highway accidents.

Hypermiling can even make fuel-sipping gas-electric hybrid cars more efficient. Chuck Thomas, 50, a computer programmer from Lewisville, Texas, said he has been getting 71 mpg from his Honda Insight, a hybrid whose EPA rating is 58 mpg, in the two years since he has been hypermiling.

Among Thomas' techniques is "pulse and glide" in which he accelerates and then coasts with the engine off until around 15 mph when he kicks the engine back on and accelerates again. "It's the automotive equivalent of skateboarding," he said.

The rest of the article can be found here.

You can calculate your vehicle's MPG in just 4 steps by:

Step 1. Filling the vehicle's gas tank completely and writing down the vehicle's odometer reading (mileage).

Example: The last time the tank was filled, the odometer reading was 32,645.1 miles.

Step 2. When it's time to refuel, filling the tank completely and writing down the number of gallons it took to fill the tank and the vehicle's new odometer reading. Once two odometer readings are taken, MPG can be calculated.

Example: The next time the tank was filled, the odometer reading was 33,001.3. It took 13.5 gallons to fill the tank.

Step 3.  Calculating the distance driven by subtracting the previous odometer reading from the new one.

Example: The distance driven would be 33,001.3 minus 32,645.1, or 356.2 miles.

Step 4.  Dividing the number of miles driven by the number of gallons it took to fill the tank. The result is the vehicle's MPG for that driving period.

Example: 356.2 miles divided by 13.5 gallons equals 26.4 miles per gallon.

The MPG for that driving period would be 26.4.

Alternate Method using Odometer:

Step 1.  Fill the vehicle's gas tank completely and re-setting the trip odometer.

Note: Sometimes it's easy to get the main odometer and trip odometer readings confused, especially if the vehicle is new.

Step 2. When it's time to re-fuel:
* Fill the tank completely
* Write down the number of gallons it took to fill the tank
* Write down the mileage on the trip odometer
* Re-set the trip odometer

Example: It took 9.5 gallons to completely fill the tank, and the trip odometer reads 335 miles.

Step 3.  Dividing the number of miles driven by the number of gallons it took to fill the tank. The result is the vehicle's MPG for that driving period.

Example: 335 miles divided by 9.5 gallons equals 35.5 MPG.

Here are is an incomplete list of some vehicle models that would make good hypermiling cars:

Ford Focus
Mercedes-Benz E320 Bluetec
Nissan Sentra
Pontiac G5
Cheverolet Aveo
Geo Prizm
Toyota Corolla
Honda Accord
Toyota Prius

Here are the most (and least) fuel efficient cars as ranked by the Federal Government at FuelEconomy.gov:

2008 Most and Least Fuel Efficient Vehicles (ranked by city mpg)
MOST EFFICIENT OVERALL		MPG
		City	Hwy
	Toyota Prius	48	45
Most and Least Fuel Efficient Cars (by EPA Size Class)		MPG
		City	Hwy
Most Efficient Two Seaters
	smart fortwo Convertible 3 cyl, 1 L, Automatic(S5), Premium	33	41
	smart fortwo Coupe 3 cyl, 1 L, Automatic(S5), Premium
	Mazda MX-5 4 cyl, 2 L, Manual(5), Premium	22	27
Most Efficient Minicompact Cars
	MINI Cooper 4 cyl, 1.6 L, Manual(6), Premium	28	37
	MINI Cooper 4 cyl, 1.6 L, Automatic(S6), Premium	26	34
Most Efficient Subcompact Cars
	Toyota Yaris 4 cyl, 1.5 L, Manual(5), Regular	29	36
	Toyota Yaris 4 cyl, 1.5 L, Automatic(4), Regular	29	35
Most Efficient Compact Cars
	Honda Civic Hybrid 4 cyl, 1.3 L, Automatic(CVT), HEV, Regular	40	45
	Toyota Corolla 4 cyl, 1.8 L, Manual(5), Regular	28	37
Most Efficient Midsize Cars
	Toyota Prius Hybrid 4 cyl, 1.5 L, Automatic(CVT), HEV, Regular	48	45
	Nissan Versa 4 cyl, 1.8 L, Manual(6), Regular	26	31
Most Efficient Large Cars
	Honda Accord 4 cyl, 2.4 L, Manual(5), Regular	22	31
	Honda Accord 4 cyl, 2.4 L, Automatic(4), Regular	21	31
Most Efficient Small Station Wagons
	Honda Fit 4 cyl, 1.5 L, Manual(5), Regular	28	34
	Honda Fit 4 cyl, 1.5 L, Automatic(5), Regular	27	34
Most Efficient Midsize Station Wagons
	Volkswagen Passat Wagon 4 cyl, 2 L, Manual(6), Premium	21	29
	Volkswagen Passat Wagon 4 cyl, 2 L, Automatic(S6), Premium	20	28
Least Fuel Efficient Cars
Least Efficient Two Seaters
Lamborghini Murcielago, 12 cyl, 6.5 L, Man(6)		8	13
Lamborghini Murcielago Roadster, 12 cyl, 6.5 L, Man(6)
Least Efficient Minicompact Cars
Aston Martin DB9 Coupe, 12 cyl, 5.9 L, Man(6)		10	16
Aston Martin DB9 Volante, 12 cyl, 5.9 L, Man(6)
Least Efficient Subcompact Cars
Bentley Continental GTC, 12 cyl, 6 L, Auto(6)		10	17
Least Efficient Compact Cars
Bentley Azure, 12 cyl, 6.7 L, Auto(S6)		9	15
Least Efficient Midsize Cars
Ferrari 612 Scaglietti, 12 cyl, 5.7 L, Auto(6)		9	16
Least Efficient Large Cars
Bentley Arnage RL, 8 cyl, 6.7 L, Auto(S6)		9	15
Least Efficient Small Station Wagons
Audi S4 Avant, 8 cyl, 4.2 L, Man(6)		13	20
Least Efficient Midsize Station Wagons
Mercedes-Benz E63 AMG, 8 cyl, 6.2 L, Auto(S7)		12	18

Below are some hypermiling guides from around the net. Keep in mind that hypermiling techniques are debated by different hypermilers and that you should do some research before implementing any techniques. Be especially careful if a technique sounds unsafe. What's more important, gas mileage or your well being?

The Ultimate Guide to Hypermiling: 100 Driving and Car Tips and Resources

Hypermiling, or driving your car “in a manner that maximizes mileage,” has become more popular among drivers worldwide, as concerns over increasing gas prices and environmental issues heighten. Whether you’re trying to make a difference by helping the environment, or you’re just aiming to save a few more dollars at the pump each month, check out this ultimate guide to hypermiling, which provides tips and resources for smart driving.

Driving Tips

Below is a list of hypermiling tips that drivers can implement while behind the wheel. We recommend practicing one or two tips at a time and gradually working your way up to the whole list so that you aren’t overwhelmed.

1. Drive a stick shift: If you’re used to driving automatic, switching over to a stick shift might take a little practice, but it’s definitely worth it. Once you have more control over the vehicle, you’ll be able to master more hypermiling tricks.
2. Stop speeding: The harder you press the gas pedal, the more gas you’re using. If you’re driving over the speed limit, you might save time, but you’re definitely wasting gas and money. Slow down a little if you can so that you’re driving at or just below the actual speed limit.
3. Coast instead of braking: When you see a stop sign up ahead or a traffic light turning yellow, immediately take your foot off the gas and let your vehicle slow down by itself. If you wait until the last possible minute to brake, then you’re wasting all the gas you used when you could have been slowing down.
4. Cruise Control: One automatic setting that actually helps hypermiling is cruise control, which prevents “you from “creeping” up in speed without realizing it,” according to Epistolary.org.
5. Put your car in neutral: Coasting with your car in neutral takes the burden off your gas pedal preventing you from wasting fuel. If you’re not driving in heavy traffic, experiment with this effective money saver.
6. Lighten the load: The heavier your car is, the harder it has to work to propel itself forward. Empty out your trunk and backseat of ice chests, beach chairs, and other items that you’re not using to lighten the load.
7. “Shift slow and low”: The site Epistolary.org urges drivers to “shift slow and low,” whenever possible to give your vehicle more mileage.
8. Drafting: This technique comes with a warning sign: according to many hypermiling experts, it is incredibly dangerous. A “deliberate form of tailgating,” the forced auto stop involves turning off your car’s engine and then following closely behind the vehicle in front of you “in order to take advantage of the reduced wind resistance in [the other car’s] immediate wake.”
9. Find a route that’s easy on your vehicle: A story in the Washington Post discusses the benefits of “optimiz[ing] your route” when implementing hypermiling tricks. Instead of taking the scenic route to work, which could include more hills, twists, and dips, try finding a route that features level roads and less traffic lights or stop signs. Generally, “a longer route with better driving conditions” can use “less gas.”
10. Park in the sun: The blogger Joe Future believes that parking your vehicle in the sun is a hypermiling tip for two reasons: “On a cold day, parking in the sun keeps your car warmer.” Also, a warmer car “will get to “auto-stop” mode faster than a cold car, so you’ll sit idling at fewer red lights while you’re waiting for auto-stop to kick in.”
11. Roll down the windows if you’re not on the highway: After the scorching hot temperatures of the summer have retreated, stop blasting the air conditioner and roll down your windows. According to Drive.com.au, “It is generally accepted that air-conditioning increases fuel consumption by about 10 percent but winding down the windows increases drag, which is also an enemy of good fuel consumption.” If you’re going to be on the highway, keeping your A/C on low is still a good idea, but if you’re taking a joy ride, think about getting a little fresh air.
12. Turn off the car before putting it in park: