The results showed that drivers could save more than 20 percent of fuel by driving economically (one in five gallons). In general the saving wa accompanied by a reduction in mean vehicle speed, but independent of speed differences, a saving of 14.7 percent was achieved by economical driving. The diesel car used 25 percent less fuel than the equivalent performance petrol car when driven normally, and 34 percent when the cars were driven economically. An extra passenger increased fuel consumption by 2 to 6 percent. There was little difference between the average fuel economy returned by men and womern drivers, although men drivers tended to give more varied results. Multiple regression analysis showed speed to be the main factor which influenced fuel consumption