Evaluating the Impact of Velocity Advisory Systems on Fuel Economy of Passenger Vehicles: A Driver Simulator Study

With increasing emphasis on sustainable mobility and efficient energy use, advanced driver assistance systems (ADAS) may potentially be utilized to improve vehicles’ energy efficiency by influencing driver behavior. Despite the growing adoption of such systems in passenger vehicles for active safety and driver comfort, systematic studies examining the effects of ADAS on human driving, in the context of vehicle energy use, remain scarce. This study investigates the impacts of a driver speed advisory system on energy use in a plug-in hybrid electric vehicle (PHEV) through a controlled experiment using a driving simulator. A mixed urban highway driving environment was reconstructed from digitalizing a real-world route to observe the human driver’s behavior with and without driving assistance. The advisory system provided drivers with an optimized speed profile, pre-calculated for the simulated route to achieve maximum energy efficiency. Participants were instructed to navigate the simulated route while the vehicle's powertrain parameters, energy consumption, and overall dynamics were monitored. In the unassisted condition, drivers operated the vehicle according to their natural driving style. In the assisted condition, real-time speed advice was given to provide drivers with a more energy-efficient driving strategy through visual feedback. The results were analyzed to evaluate the impact of speed advisory systems on vehicle dynamics, powertrain use, and energy consumption metrics. The assisted driving condition resulted in smoother driving patterns, optimized powertrain operation, and notable fuel economy improvements compared to unassisted driving.