Vehicle acceleration and braking tracking
The Quartix Vehicle Tracking System monitors the speed of the vehicle every second; acceleration and braking indexes are calculated by the quantity of increases and decreases in miles per hour each second. These are then weighted according to how severe they are and averaged over a driving hour to calculate the Acceleration Index and the Braking Index.
This speedometer shows the 10 levels of acceleration and braking, and each level has a weighting based on its severity. As such, speed reaching 6 mph in a second is a level 3 acceleration. Speed which goes down by 9 mph equates to level 3 braking, and so on.
Calculating the fleet driving style score – Example weightings of acceleration and braking events are shown in the table opposite.
The acceleration index is the sum of all the acceleration incidents, each multiplied by their severity and finally divided by the driving time in hours. The braking index is worked out in a similar way, except that the levels of speed change are slightly different, as are the severity weightings.
Example. If a vehicle is driven for 2 hours, and during that time there are 20 level 1 accelerations (severity 0.2) and 15 level 2 accelerations (severity 0.5) then the acceleration index is (20×0.2+15×0.5)/2 =5.75 This is a relatively low index, showing modest acceleration.
The Fleet Driving Style Score is the overall score out of 100 for a given period, typically a day, a week or a month. The Quartix fleet tracking system will add up all the weighted acceleration and braking events with their severities, calculate the total driving time and work out the Acceleration and Braking Indexes for all your fleet drivers.
Distribution of daily fleet driving style scores – This fleet tracking graph shows an analysis of 830,000 journeys, giving scores for 64,000 ‘driver days’.
As described above, the calculation of the acceleration and braking indexes and hence the fleet driving style score, are based on a ‘per hour’ calculation. Calculating the average per hour means that no fleet drivers are penalised for driving more or less than any other driver.
The Quartix fleet tracking system calculates the Daily Fleet Driving Style Score for each day, based on the amount of driving for that day or shift (excluding any parts of trips before the start or after the end of the day/shift). We apply colours to the Daily Fleet Driving Style scores as shown on the plot opposite. If the score is >80 it is green – this represents the best 30% of fleet drivers. If the score is between 50 and 80 it is shown as amber, and this represents the middle 50% of daily scores. 50 or below is red, and that’s the worst 20%.