Apparatus and method for determining an advised driving speed

1. A method of evaluating an advised driving speed of a geared vehicle traversing a particular portion of a road network, comprising:

accessing first predetermined data indicative of the variation in average fuel consumption for the vehicle with speed of the vehicle, wherein the first predetermined data comprises a fuel consumption per speed histogram having a plurality of bins, each bin associated with an average fuel consumption value that is computed based on fuel consumption values received from the vehicle while traveling at a corresponding speed;

using the first predetermined data to determine data indicative of average fuel consumption for the vehicle for a plurality of speeds within a range based on a speed limit for the portion of the road network being traversed;

using second predetermined data indicative of a variation in a likelihood of the vehicle being in a highest gear with a speed of the vehicle to determine data indicative of a likelihood of the vehicle being in the highest gear for the plurality of speeds within the range based on the speed limit for the portion of the road network being traversed;

evaluating the advised driving speed of the vehicle based at least in part on the determined data indicative of average fuel consumption for the vehicle for the range of speeds and the determined data indicative of a likelihood of the vehicle being in the highest gear for the range of speeds; and

providing an indication of the determined advised driving speed to a driver of the vehicle, thereby informing the driver of the vehicle of an optimal speed of travel for the vehicle for the portion of the road network being traversed.

2. The method of claim 1 , further comprising generating the fuel consumption per speed histogram for the vehicle, said generating comprising:

receiving a plurality of fuel consumption values of the vehicle;

receiving a corresponding plurality of speeds of the vehicle, wherein each speed of the vehicle indicates the speed for which a corresponding fuel consumption value was determined;

assigning each of the fuel consumption values to one of a plurality of bins of a histogram based on the corresponding speed of the vehicle at which the fuel consumption value was determined; and

evaluating an average fuel consumption value for each bin of the histogram by averaging the fuel consumption values within each bin.

3. The method of claim 1 , wherein the second predetermined data indicative of the variation in a likelihood of the vehicle being in the highest gear with speed of the vehicle is a likelihood of the vehicle being in the highest gear per speed histogram.

4. The method of claim 3 , further comprising generating the likelihood of the vehicle being in the highest gear per speed histogram for the vehicle, said generating comprising:

receiving, for each of a plurality of speeds of the vehicle, a value indicative of whether the vehicle was its highest gear at that speed;

assigning each of the values indicative of whether the vehicle was its highest gear to one of a plurality of bins of a histogram based on the corresponding speed of the vehicle at which the value was determined; and

evaluating an average value for each bin of the histogram by averaging the values indicative of whether the vehicle was its highest gear within each bin.

5. The method of claim 1 , comprising:

determining a score value for each of the plurality of speeds within the range based on a speed limit for the portion of the road network being traversed, said score value being determined using the first predetermined data and the second predetermined data; and

setting the advised driving speed of the vehicle as a speed from the plurality of speeds within the range based on the determined score values.

6. The method of claim 1 , comprising triggering a determination of the advised driving speed when there is change in a speed limit and/or an expected driving speed for the portion of the road network being traversed.

7. The method of claim 6 , wherein the determination of the advised driving speed is triggered when the change in the speed limit and/or expected driving speed is more than a predetermined threshold.

8. The method of claim 1 , wherein providing an indication of the advised driving speed to the driver comprises displaying a graphical indication of the advised driving speed on a display device within the vehicle.

9. The method of claim 8 , wherein the determined advised driving speed is displayed on the display device in combination with at least one of: the current speed of the vehicle; and the speed limit for the portion of the road network being traversed.

10. The method of claim 1 , comprising transmitting the determined advised driving speed to a remote server for use in determining a score indicative of the driver's compliance of the advised driving speed during a journey.

11. An apparatus for evaluating an advised driving speed of a geared vehicle traversing a particular portion of a road network, comprising at least one processor and a memory containing instructions that, when executed by the at least one processor, cause the apparatus to:

access first predetermined data indicative of the variation in average fuel consumption for the vehicle with speed of the vehicle, wherein the first predetermined data comprises a fuel consumption per speed histogram having a plurality of bins, each bin associated with an average fuel consumption value that is computed based on fuel consumption values received from the vehicle while traveling at a corresponding speed;

use the first predetermined data to determine data indicative of average fuel consumption for the vehicle for a plurality of speeds within a range based on a speed limit for the portion of the road network being traversed;

use second predetermined data indicative of a variation in a likelihood of the vehicle being in a highest gear with a speed of the vehicle to determine data indicative of a likelihood of the vehicle being in the highest gear for the plurality of speeds within the range based on the speed limit for the portion of the road network being traversed;

evaluate the advised driving speed of the vehicle based at least in part on the determined data indicative of average fuel consumption for the vehicle for the range of speeds and the determined data indicative of a likelihood of the vehicle being in the highest gear for the range of speeds; and

provide an indication of the determined advised driving speed to a driver of the vehicle, thereby informing the driver of the vehicle of an optimal speed of travel for the vehicle for the portion of the road network being traversed.

12. The apparatus of claim 11 , wherein the instructions, when executed by the at least one processor, further cause the apparatus to:

determine a score value for each of the plurality of speeds within the range based on a speed limit for the portion of the road network being traversed, said score value being determined using the first predetermined data and the second predetermined data; and

set the advised driving speed of the vehicle as a speed from the plurality of speeds within the range based on the determined score values.

13. The apparatus of claim 11 , further comprising a display device, and wherein the instructions, when executed by the at least one processor, cause the apparatus to display a graphical indication of the advised driving speed on the display device.

14. The apparatus of claim 11 , wherein the apparatus comprises one of: a vehicle tracking device, a portable navigation device, and a navigation device integrated in the vehicle.

15. The apparatus of claim 11 , further comprising a wireless transmitter configured to output the determined advised driving speed to a further device.

16. A non-transitory computer readable medium comprising instructions which, when executed by at least one processor of an apparatus comprising the at least one processor, cause the apparatus to perform a method of evaluating an advised driving speed of a geared vehicle traversing a particular portion of a road network, the method comprising:

accessing first predetermined data indicative of the variation in average fuel consumption for the vehicle with speed of the vehicle, wherein the first predetermined data comprises a fuel consumption per speed histogram having a plurality of bins, each bin associated with an average fuel consumption value that is computed based on fuel consumption values received from the vehicle while traveling at a corresponding speed;

using the first predetermined data to determine data indicative of average fuel consumption for the vehicle for a plurality of speeds within a range based on a speed limit for the portion of the road network being traversed;

using second predetermined data indicative of a variation in a likelihood of the vehicle being in a highest gear with a speed of the vehicle to determine data indicative of a likelihood of the vehicle being in the highest gear for the plurality of speeds within the range based on the speed limit for the portion of the road network being traversed;

evaluating the advised driving speed of the vehicle based at least in part on the determined data indicative of average fuel consumption for the vehicle for the range of speeds and the determined data indicative of a likelihood of the vehicle being in the highest gear for the range of speeds; and

providing an indication of the determined advised driving speed to a driver of the vehicle, thereby informing the driver of the vehicle of an optimal speed of travel for the vehicle for the portion of the road network being traversed.