TOKYO - Nissan's Eco Pedal, unveiled here on Monday, promises to trigger a range of reactions from consumers who are either pleased by its fuel-saving capability or enthusiasts who are put off by its micromanagement of their driving style. In any case, the system can be turned on or off based on the driver's preference.

The Eco Pedal is designed to provide a 'counter push-back control mechanism' if it senses 'excess pressure' on the accelerator. In other words, it does not like lead foots. The premise of this new technology, which Nissan says is a 'world first,' is to help the driver get an immediate sense that he or she 'could be using more fuel than required.'

'An eco-driving indicator integrated into the instrument panel feeds the driver with real-time fuel consumption levels to help improve his/her driving behavior,' Nissan said in a statement.

It says it plans to commercialize the Eco Pedal during 2009, but the company does not indicate how much the technology will add to the price of a vehicle. It says that drivers can expect to improve fuel efficiency by 5-10 percent, depending on driving conditions. That amount is based on Nissan's internal research data and apparently has not been confirmed by such independent government agencies as the EPA.

The automaker does not say whether it will be offered on all of its products, including the .

The system calculates the rate of fuel consumption and transmission efficiency during acceleration and cruising and then calculates the optimum acceleration rate, Nissan said. 'When the driver exerts excess pressure on the accelerator, the system counteracts with the pedal push-back control mechanism,' according to the automaker.

A gauge on the instrument panel shows the 'optimal level for fuel-efficient driving.' A green light shows that you're exerting the proper pressure on the pedal to achieve the best fuel economy; it flashes when it detects increased acceleration and turns to amber as a final warning.