A computer implemented method of providing coasting information to a vehicle driver, comprising: determining a location of a coasting area, based on a location of a navigation device corresponding to a current position of the vehicle and a predetermined or predicted route being followed by the vehicle, wherein determining a coasting area comprises: determining an end point location of a coasting area based upon a location in digital map data of an expected decrease in speed of a vehicle traversing a road network represented by the digital map data, the digital map data being used to determine upcoming sections of the road network associated with a target speed, wherein the target speed is associated with the end point location; and determining a start point location of the coasting area based upon the end point location and a coasting distance; and generating coasting information indicative of the coasting area having the start point and end point locations (521, 522); characterised by: the start point location being determined dynamically according to a speed differential between the current vehicle speed and the target speed, together with a deceleration of the vehicle during coasting, the deceleration being dependent on the current speed; a distance being determined for each speed value between the current speed and the target speed, and each individual distance aggregated to determine the coasting distance; and outputting the coasting information indicative of the coasting area for provision to the vehicle driver based upon a difference between a current speed of travel of the navigation device and the target speed, when the difference between the current speed of travel and the target speed is at least a predetermined speed. determining a location of a coasting area, based on a location of a navigation device corresponding to a current position of the vehicle and a predetermined or predicted route being followed by the vehicle, wherein determining a coasting area comprises: determining an end point location of a coasting area based upon a location in digital map data of an expected decrease in speed of a vehicle traversing a road network represented by the digital map data, the digital map data being used to determine upcoming sections of the road network associated with a target speed, wherein the target speed is associated with the end point location; and determining a start point location of the coasting area based upon the end point location and a coasting distance; and generating coasting information indicative of the coasting area having the start point and end point locations (521, 522); characterised by: the start point location being determined dynamically according to a speed differential between the current vehicle speed and the target speed, together with a deceleration of the vehicle during coasting, the deceleration being dependent on the current speed; a distance being determined for each speed value between the current speed and the target speed, and each individual distance aggregated to determine the coasting distance; and outputting the coasting information indicative of the coasting area for provision to the vehicle driver based upon a difference between a current speed of travel of the navigation device and the target speed, when the difference between the current speed of travel and the target speed is at least a predetermined speed. determining an end point location of a coasting area based upon a location in digital map data of an expected decrease in speed of a vehicle traversing a road network represented by the digital map data, the digital map data being used to determine upcoming sections of the road network associated with a target speed, wherein the target speed is associated with the end point location; and determining a start point location of the coasting area based upon the end point location and a coasting distance; and generating coasting information indicative of the coasting area having the start point and end point locations (521, 522); characterised by: the start point location being determined dynamically according to a speed differential between the current vehicle speed and the target speed, together with a deceleration of the vehicle during coasting, the deceleration being dependent on the current speed; a distance being determined for each speed value between the current speed and the target speed, and each individual distance aggregated to determine the coasting distance; and outputting the coasting information indicative of the coasting area for provision to the vehicle driver based upon a difference between a current speed of travel of the navigation device and the target speed, when the difference between the current speed of travel and the target speed is at least a predetermined speed. the start point location being determined dynamically according to a speed differential between the current vehicle speed and the target speed, together with a deceleration of the vehicle during coasting, the deceleration being dependent on the current speed; a distance being determined for each speed value between the current speed and the target speed, and each individual distance aggregated to determine the coasting distance; and outputting the coasting information indicative of the coasting area for provision to the vehicle driver based upon a difference between a current speed of travel of the navigation device and the target speed, when the difference between the current speed of travel and the target speed is at least a predetermined speed.