A method for guidance of driver behavior during driving of a vehicle (1) in hilltop driving: the steps of continuously determining topography along the vehicle's itinerary for determining a profile of the vehicle's speed (v); presenting (S2) the vehicle driver with suggestions for action concerning the driving of the vehicle for a desired reduction of fuel consumption, the action includes reduced power mobilization before a hilltop transition. A profile of the vehicle speed (v) is determined as a result of the action, whereby the step of presenting (S2) the vehicle's driver with suggestions for said action, is subject to consideration to subconditions. The subconditions include requirements in response to reduced power mobilization, the speed of the vehicle (1) relative to a reference level (vref) should: drop by a predetermined largest amount before the hilltop transition; drop by a predetermined smallest amount before the hilltop transition; reach or exceed the reference level (vref) after the hilltop transition. Also disclosed is a system for guidance of driver behavior during driving of a vehicle in hilltop driving, a motor vehicle practicing the method and a system and a computer program for executing the method.