Good ideas all, but the driving style can make a big difference too, especially for stop and go city driving in a non-hybrid vehicle.
Example: When a distant traffic light is red and cars are already waiting at the intersection, take your foot off the gas or turn off the cruise control. Coast to the light using natural friction to slow down instead of wearing out your brake pads in the last few seconds to waste the gasoline you have purchased.
If you travel the same route every day learn which intersections have synchronized lights. Often when not speeding up to the posted speed limit, you can arrive at the next light just after it has turned green and traffic ahead of you has already begun to move. No brakes, no waste.
Excellent point about driving style. Unfortunately, during rush hour traffic, your fellow drivers will probably not allow you to coast toward the red light. As soon as the space in front of you exceeds 1.25 car lengths, someone will zoom into that space.
I realize that it is an expensive experiment, but that XL1 is amazing! You could drive from SF to LA or Boston to Washington DC on one tank of gas.
And that tank of gas is less than 3 gallons!
This really shows the advantage of diesel, which has low highway mileage, and a hybrid, which has low city mileage. I'm surprised it hasn't been done before now. Trains have been diesel hybrids for decades now.
I'm amazed when people debate over hybrids vs diesels. The answer is, both!
I look forward to VW coming out with more conventional cars that are diesel hybrids.
Actually for most of the last 40 years, car manufacturers have been thinking very little about fuel efficiency and emissions. Instead the concentrated on power, acceleration etc, and in the US often on quietness - a larger engine turning over more slowly is quieter, and frankly ridiculous body size - how many people really need an SUV or a 4x4 rather than like the image of driving one?
As recently as the mid 2000's they were vigourously fighting against the European Union bringing in targets for vehicle carbon dioxide emissions (which unavoidably equate to fuel consumption) using a variety of specious arguments. At the time the average emissions per vehicle were around 180g CO2/km with plenty of the German luxury cars producing up to twice that figure. The standard was introduced at a 120g level (averaged across the fleet - so if you sold a car with high emissions it needed to be balanced out by selling low emissions ones). The consequence has been a very fast deployment of lower emissions vehicles, plenty of them with emissions below 100g even without using any hybrid technology, and those same German manufacturers now sell luxury cars (often hybrid) with emissions well below the previous average number.
Since the rise in the price of oil (up by a factor of 4 in 10 years) the lower fuel consumption is very populat with consumers, as are the lower taxes associated with low emissions. But without standards being set, the manufacturers would have dragged their feet.
I'm all in favor of ultra efficient cars. However, while the research continues, we would get the greatest bang for the buck (and save the most gas) by doing the easy things first. It is illegal to leave a truck idling in New York City yet every vehicle on the road idles at stop lights and in traffic jams. Turning off the engine when stopped (as my hybrid does) would save gas, pollution, and reduce noise - and the auto-start technology is fast and reliable. The SUV behind me at the stop light uses more gas stopped than I do driving.
If the car navigation systems can provide advanced information on the speed at which you should drive to cross the enxt signal while it is green ( without crosssing the speed limit off-course) , then it can save a lot of stoppage time ( and in turn the engine idling time)
Another thought _ Most of us commute to the office alone but have a bigger car for family outings n weekends . If we are able to swap arrangement with the car companies to swap between a small car and a big car then there could be a lot of fuel savings on weekdays plus the added advantage of less crowed streets on weekdays because of more small cars.