I've been playing with values in my fuel economy spreadsheet, and come to the conclusion that one of the biggest problems we face with fuel economy is excessive speed.
For example, I save 1/4 of the fuel with my car by going 20kph slower, from 100kph to 80kph. With other driving techniques, the difference is more. e.g. P&G ICE ON, 33%, P&G ICE OFF, 37%.
I simulated it with a typical full sized sedan (Ford Falcon), and the gain was 20%, and getting roughly 4.8l/100km at that speed.
But that is really just the beginning. The fact is, most traffic consists of one person in the car. The ideal motorized vehicle for 1 person is in fact a motorcycle or a low drag VW 1 litre type commuter, capable of getting about 1l/100km or less with a ~100cc engine. Part of the reason we don't see more travel with such vehicles (motorcycles) is because the weather is inconsistent, but also because long distance travel is usually best via freeway, and freeways usually have 100+kph traffic making them dangerous.
The next logical step would be a move to a human powered transport system, especially velomobiles, most likely with electric assist/regeneration to smooth out the hills and recover most of the energy from the downhill slopes otherwise lost to braking. This would need widespread lanes with a further reduction in maximum speed. Ultimately the desired situation would be that every road must be restricted to say 40-50kph, and that all highways would have at least one such lane.
There are other advantages to limiting top speed. The slower you go, the less energy is lost when you brake. Because KE = 0.5mv^2, slowing from 100kph versus 50kph to a stop loses 4 times as much energy and hence fuel. Collisions are less dangerous for that same reason and more avoidable because of increased reaction time.
The fact is, in most countries there is a maximum speed limit but no minimum speed limit except for roads like autobahns. Thus, there is no reason why a person can't go a maximum of 80kph or even 70kph (45-50mph) on every road.
I've been doing this for a few weeks now (max of about 80kph), and in multi lane highways there have been a few tailgaters, but no one has beeped me yet. The fact is, if you are in the slow lane and they don't like your speed, they have the option of using a faster lane.
The idea of making this a movement is similar to the "Critical Mass"
idea of bicycles. Except that you can do it all the time, especially if you have a car (makes you difficult to pass or intimidate). If enough people do it every day, it will effectively act as a speed limit on the whole slow lane, bringing change much sooner than a bike ride every month could possibly do. And that will be the ticket to make motorcycles, enclosed commuting type vehicles and eventually velomobiles more practical vehicle choices.
Maybe some catchy slogans and bumper stickers would help the idea spread more rapidly and the idea become a reality sooner (population density will do it eventually, regardless). I see that "ecodriving.org" is taken as a website (com as well). I see that "GoSlow.org" is taken as well.
A website could explain other seemingly crazy things we do, for example, not accelerate towards red lights. Enough people exhibiting the same behavior will reduce the rage from the hotheads, and the rationale will be understood (and perhaps embraced).
But anyway, that's the idea. Got any comments, slogans, or ideas?