Trucks with a gross vehicle weight above 12 tons and of year model 1988 or later shall as from 1992 be equipped with a speed regulator. The Road Administration, Region Skåne, made an agreement with a number of truck companies to set speed regulators with 85 km/h as maximum speed. The truck owners guaranteed that the speed regulators in the previous year were set at 89 km/h. The speed regulators were reset in June 2003. The agreement between the Road Administration and the truck owning companies included six companies and in all 17 trucks. Data on fuel fillings and odometer readings per month, both before and after the speed regulator resetting, was only available for 12 trucks belonging to five companies. The data analysis showed an increase in fuel consumption in the after situation. Different methods of analysis give somewhat different results with an increase of more than 3% at the most. The average air temperature in the after situation was somewhat higher than before the speed regulators were reset. The analyses show a temperature effect of 0.3% decrease in fuel consumption, from before to after.