An integrated driving safety-volatility-operational performance indicator

Abstract

Understanding driver behaviour is important to improve road safety and it is essential that drivers become aware of their contribution to road traffic impacts through their driving styles. Driving on the edge of critical safety distances yields unsafety road conditions. Volatility can be defined as the extent of variations in driving, which can be characterized by sudden accelerating/braking, lane changing, and the unusually high speed for road conditions. The operational performance of the vehicle led by the driver also represents a key component regarding the efficiency of the driving. Therefore, the objective of this work is to develop an integrated indicator that objectively assesses driver behaviour based on three key components: (i) safety; (ii) volatility, and (iii) operational performance, using the respective variables: (i) time headway and stop distance, (ii) acceleration and vehicular jerk and (iii) Vehicle Specific Power mode. The indicator provides an assessment to the driver when performing a driving task and returns an overall evaluation, at the end of each trip. A microscopic traffic model VISSIM with a COM API interface was used. The case study involves a highway scenario. The model was calibrated based on the following data: a) traffic; b) vehicle dynamics from test vehicles on two highways with different specificities (e.g., slope and traffic volumes). After performing a trip, each driver receives a rating based on the proposed Driving Safety-Volatility-Operational Performance Indicator. Safety is evaluated using time headway and stop distance, volatility is assessed by acceleration and vehicular jerk, and operational performance is rated through Vehicle Specific Power mode. The experiments show the relevance of the developed indicator in evaluating the driving task.