The prototype was tested in and around Enschede, the Netherlands. The computer program in the device keeps track of essentials like speed, steering wheel angle and distance to the vehicle in front, constantly calculating what the driver should be doing to minimize fuel consumption. The program takes a dim view of idling, a notorious gasoline waster, and of that staple of New York City taxi drivers, rapid acceleration followed immediately by an equally rapid deceleration. Van der Voort devised the computer program and dashboard display with the help of two advisers as part of the work for her doctorate. In the long term, van der Voort acknowledged, the bulk of gasoline savings will probably come from improvements in engine efficiency, not from changes in driving habits.
Many dashboards can already tell drivers, for instance, how much fuel they are using for a maneuver.
It gives you constant feedback during a trip on many ways to improve fuel efficiency. Van der Voort and her colleagues tested the program first in computer-controlled driving simulations and then on the road. Red warnings were given when two minutes had elapsed. Drivers in urban areas did even better, reducing fuel use by 23 percent. In the actual road tests that followed the simulated ones, the advice was shown without the colored warning light to make the display less distracting.