My '88 BMW 325i (yes a car that was produced 19 years ago) has a little needle showing fuel consumption in l/100kms. I know, I know... a 168HP skateboard isn't a green car by any means and I should get a lame old Prius. But that little needle has helped me be aware of when and how I'm burning gas. It's awesome to have the feedback, but it's far better if it's an actual dynamic reading rather than an on and off light.

I had an '87 BMW 325, I loved that little econo-gauge! Too bad every single part seemed to cost $400.

Oh boy, cell phone in one hand, eyeball on the econometer. More gas would be saved if more attention was paid to driving.
Traffic would move faster and everyone would save gas by getting to their destinations faster. The road would also be a safer place for the people who have liberated themselves from the car.

This is in fact old school technology that should be in everycar. My wife's now getting rather old but still reliable 1991 BMW 325 has an extra little gage that gives a read out of fuel mileage. The more your hammer down the gas peddle the lower the gage drops. Let up and up goes the arrow. It becomes a great game while your driving to try and keep the gas mileage as high as possible. Any new ECO gage should include direct feed back to the driver about exactly what fuel mileage they are getting at that moment based on their current driving style.

I don't think fuel economy feedback falls into the same category as cell phones. After all, you do have to check your instruments once in a while if only to see your speed, and with LCDs and graphs you can easily check them when the car is stopped or whatever.

The problem with cellphones is that you are in a conversation, but unlike conversations with people who are in the car (they tend to not bother you too much during tricky driving because their safety depends on you paying attention), they demand your attention regardless of what you are doing.

The eco light or the LCD can easily be ignored when it's not the right time to check them and when you do check them, they don't require much attention and not for very long.

Most car's computer controlled engines have all the data available. All you need is this device http://www.thinkgeek.com/gadgets/electronic/8426/ to display it.

We've had a Prius for almost 5 years (the LCD shown is from a Prius), and I've had the same basic thought for a long time: if people had immediate feedback about what their driving habits (e.g., jackrabbit starts, driving faster than the speed limit, driving too close requiring heavy braking) were costing them in terms of fuel enconomy, it would save quite a bit of gas overall. But people do all those things and more, and then wonder why the MPG they get doesn't even come close to the EPA estimates. (And yes, I know the EPA estimates are messed up, but a lot of the difference is people's driving habits.) Having the bar gauge giving almost immediate feedback on your mileage tells you a lot, and can make you a safer driver (e.g., longer following distance) if you learn from it.

Certainly not a new concept - UHaul trucks that I have driven have the enonomy lights in them for years.

I wonder if any studies have been performed about the increased fuel consumption caused by creating traffic jams through nonaggressive driving? If someone (usually driving a corolla) is slow turning left and causes two fewer cars from also turning left, then those two cars must idle for another few minutes. Also, slow drivers tend to cause road rage, which makes other drivers go nuts and drive aggressively to get around them, burning extra fuel. The solution is to have a "toyota only" lane, and put it preferably far away from mine!

I had a 1986 cadillac seville that had a digital readout of the miles per gallon I was getting .. whats the big deal . don't these new engineers have any new idea

Wow. My dad's 1975 Marquis Brougham had exactly the same thing on its dashboard. The game we used to play was to see how often we could get it to turn on and for how long.

Way to go, Toyota.

This is a great idea! I drive a Volvo station wagon that is shamefully not as gas friendly as I would like. The best feature however is that it tells me my avg MPG so I can be aware when I am driving like a hog and burning gas. Now I play a little game where I try to get my avg mpg up to beat my "record" from the last time I refilled. It is a great way to make people constantly aware.

My uncle's 1962 Pontiac Gran Prix had a guage on the console that performed a similar function. When you were driving economically it indicated green.
If you were driving less than economically it indicated yellow. And if you had your foot in it, it indicated red.
I remember him laughing about it.