It factors in duration, magnitude and frequency of speeding, braking, and acceleration, along with the time and weather conditions of these events. These factors are known predictors of crash events and are used by the insurance industry to evaluate risk. The scoring algorithm also factors in idling as a key behavior to monitor and mitigate.
How Scoring Works
Scores are generated daily for the previous day’s driving with a score of 100 representing the best driver of the fleet (a driver who has driven the most with no events the previous day). Scores generated for Braking, Speeding, Acceleration and Idling are weighted to form a composite Driver Score. This Driver Score allows workers to be compared to each other and across time, while providing an indication of the ‘risk’ associated with the driver.
Braking and Acceleration Scores
Individual Hard Braking and acceleration events during a particular day are assigned an Event Score using the magnitude of an event together with spatial and temporal conditions associated with the event. The sum of all Event Scores in a day is normalized by the number of miles driven that day for each driver and is then converted to a score between 0 and 100.
Speeding events follow a similar approach as Braking and Acceleration Scores. The magnitude of speeding events is arrived at by comparing the average speed of the speeding event with the maximum posted speed limit of the state in which the speeding event occurred. Magnitudes of the speeding events are assigned values based on these exceedances. The duration and spatio-temporal conditions of each event are also considered in determining the magnitude. The daily Speeding Score for a driver is computed after normalizing for the total miles driven that day and adjusting for relative proportion of miles driven.
Idling scores are based on the proportion of trip idling time to the total trip time over the entire day. In order to factor in unavoidable idle times such as at stop lights, the idling score is not penalized where the overall idling proportion is less than ten percent. The proportion of idling time to total trip time above ten percent is converted to an Idling Score and adjusted for the relative miles driven.
Overall Driver Score
Individual component scores (braking, speeding, acceleration and idling) are weighted to form a composite weighted average that makes up the ‘Driver Score’. This overall Driver Score provides a good indication of the level of risk associated with a worker’s driving: