Adaptive Cruise Control System Field-Tested in Sweden Assessed Speed and Fuel Consumption Benefits.
An Automated Vehicle Fuel Economy Benefits Evaluation Framework Using Real-World Travel and Traffic Data
Designed to improve driving safety and comfort, Adaptive Cruise Control (ACC) is an advanced driver-assistance feature that automatically adjusts vehicle speed to maintain a safe distance from vehicles in front. This study compared the operation and fuel economy of vehicles in ACC and non-ACC modes based on large-scale field test data collected by a car company, from vehicles traveling on the designated “Drive Me” project road network in Gothenburg, Sweden. A total of 93 ACC vehicles consisting of three types of diesel automatic vehicle models were driven by employees and family members of the car company on more than 18,590 trips over the Drive Me route during 2010-2011.
In this study, the selected Drive Me route for field-testing the ACC was a 40-km route with typical commuters making up the driver population that would potentially benefit from an automated vehicle (AV). The field test included 93 vehicles equipped with ACC, which used a radar sensor to detect the distance to the vehicle ahead and adjusted the ACC-equipped vehicle's speed to maintain a preferred following distance. Similar to a traditional cruise control request, drivers could activate ACC manually, deactivate ACC by braking, or momentarily override it by pressing the accelerator pedal. Travel data of the test vehicles were classified by driving mode (ACC vs. non-ACC) and driving conditions including traffic speed and road grade. The results from the data logging fleet were used to estimate the aggregate fuel consumption differences at the Drive Me road network for vehicles traveling in ACC vs. non-ACC modes based on appropriately weighting the total amount of travel that took place on the network under different driving conditions.
- This study revealed that travel-weighted fuel consumption rate for vehicles in ACC mode was about five to seven percent lower than vehicles in non-ACC mode when traveling at similar conditions.
- The statistical analysis of the speed data indicated that the mean speed of ACC samples (81 kilometers per hour [kph]) was about four percent higher than that of the non-ACC samples (78 kph), significant at the 95 percent confidence level.