System and method for providing an indication of driving performance
A method of providing an indication of driving performance involves obtaining a forward acceleration and speed of a vehicle. A forward acceleration threshold value is identified for use in identifying excessive forward acceleration of the vehicle based on the determined speed of the vehicle. For any vehicle speed within a range of vehicle speeds, the acceleration threshold value is defined by a function based on the determined speed of the vehicle, wherein the forward acceleration threshold value according to the function varies continually with vehicle speed over the range of vehicle speeds. The determined forward acceleration of the vehicle is compared with the determined acceleration threshold value, and an indication of an excessive forward acceleration driving event is generated when the determined forward acceleration exceeds the determined acceleration threshold value.
1. A non-transitory computer readable medium having a computer program product stored therein, the computer program product comprising instructions which, when executed by one or more processors of a system, cause the system to, during a trip undertaken by a vehicle, continually:
obtain a forward acceleration and speed of the vehicle;
determine whether the obtained speed of the vehicle is within a range of vehicle speeds, and, when the obtained speed of the vehicle is within the range of vehicle speeds:
calculate the vehicle forward acceleration threshold value using an acceleration threshold function,
wherein the acceleration threshold function takes the obtained speed of the vehicle as a variable input, and provides the vehicle forward acceleration threshold value as an output,
wherein, according to the acceleration threshold function, the vehicle forward acceleration threshold value varies continuously with the obtained speed of the vehicle and decreases with increasing vehicle speed over the range of vehicle speeds;
comparing the obtained forward acceleration of the vehicle with the calculated vehicle forward acceleration threshold value; and
generating an indication of an excessive forward acceleration driving event when the obtained forward acceleration exceeds the calculated vehicle forward acceleration threshold value.
2. The non-transitory computer readable medium of claim 1 , wherein the vehicle forward acceleration threshold value according to the acceleration threshold function defines a curve over the range of vehicle speeds.
3. The non-transitory computer readable medium of claim 1 , wherein the acceleration threshold function includes an aerodynamic drag component, a rolling resistance component, an inertial resistance component, and a climbing resistance component.
4. The non-transitory computer readable medium of claim 1 , wherein the acceleration threshold function is based on a pair of predefined acceleration and speed values and is defined such that, when the obtained speed is the predefined speed value, the vehicle forward acceleration threshold is the predefined acceleration value.
5. The non-transitory computer readable medium of claim 4 , wherein the predefined speed value of the predefined pair of acceleration and speed values corresponds to a lower limit of the range of vehicle speeds.
6. The non-transitory computer readable medium of claim 4 , wherein the vehicle forward acceleration threshold value is defined by a constant predefined threshold for vehicle speeds less than the predefined speed value.
7. The non-transitory computer readable medium of claim 6 , wherein:
the acceleration threshold function is based on a pair of predefined acceleration and speed values and is defined such that, when the obtained speed is the predefined speed value, the vehicle forward acceleration threshold is the predefined acceleration value, and
the constant predefined threshold value corresponds to the acceleration value of the predefined pair of acceleration and speed values.
8. The non-transitory computer readable medium of claim 1 , wherein the range of vehicle speeds over which the acceleration threshold function is used to determine the vehicle forward acceleration threshold has an upper limit, and, when the vehicle speed exceeds the upper limit, a constant acceleration threshold is used.
9. The non-transitory computer readable medium of claim 1 , wherein the indication of an excessive acceleration driving event is generated when the obtained forward acceleration exceeds the determined vehicle forward acceleration threshold value for more than a predetermined time period.
10. The non-transitory computer readable medium of claim 1 , comprising calculating a plurality of vehicle forward acceleration threshold values for use in identifying excessive forward acceleration of the vehicle based on the obtained speed of the vehicle, wherein each vehicle forward acceleration threshold value is in respect of a different severity level, and each severity level is associated with a respective pair of predefined acceleration and speed values, wherein each forward acceleration threshold value is calculated using the acceleration threshold function with the applicable pair of predefined acceleration and speed values.
11. The non-transitory computer readable medium of claim 1 , comprising using the generated indication to display output to a user indicative of the harsh acceleration driving event, and optionally the severity of the event.
12. The non-transitory computer readable medium of claim 1 , comprising obtaining data indicative of an acceleration of the vehicle, and determining the forward acceleration of the vehicle from the obtained acceleration data.
13. A non-transitory computer readable medium having a computer program product stored therein, the computer program product comprising instructions which, when executed by one or more processors of a system, cause the system to, during a trip undertaken by a vehicle, continually:
obtain a forward acceleration and speed of the vehicle;
determine whether the obtained speed of the vehicle is within a range of vehicle speeds, and, when the obtained speed of the vehicle is within the range of vehicle speeds:
calculate the vehicle forward acceleration threshold value using an acceleration threshold function, wherein the acceleration threshold function is dependent upon a mass of the vehicle;
estimate the mass of the vehicle for use in the acceleration threshold function using data indicative of an energy consumption of the vehicle;
wherein the acceleration threshold function takes the obtained speed of the vehicle as a variable input, and provides the vehicle forward acceleration threshold value as an output;
wherein, according to the acceleration threshold function, the vehicle forward acceleration threshold value varies continuously with the obtained speed of the vehicle and decreases with increasing vehicle speed over the range of vehicle speeds;
comparing the obtained forward acceleration of the vehicle with the calculated vehicle forward acceleration threshold value; and
generating an indication of an excessive forward acceleration driving event when the obtained forward acceleration exceeds the calculated vehicle forward acceleration threshold value.
14. The non-transitory computer readable medium of claim 13 , wherein estimating the mass of the vehicle further comprises using the obtained forward acceleration and speed of the vehicle.
15. The non-transitory computer readable medium of claim 13 , wherein the instructions, when executed by the one or more processors, cause the system to:
obtain an energy consumption of the vehicle; and
use, when the forward acceleration of the vehicle is above a predefined threshold, and optionally additionally when the speed of the vehicle is above a predefined threshold, the energy consumption, forward acceleration, and speed of the vehicle to determine an estimate of the mass of the vehicle.
16. The non-transitory computer readable medium of claim 13 , wherein a mass estimation is obtained for each one of a plurality of identified or different times, and the instructions, when executed by the one or more processors, cause the system to obtain an average mass based upon the plurality of mass estimations.
17. The non-transitory computer readable medium of claim 16 , wherein different times is a time during a single trip.
18. The non-transitory computer readable medium of claim 13 , wherein the energy consumption data is real time energy consumption data.