Does adaptive cruise control really save fuel? Is Volvo's research conclusion accurate?

Self-driving cars are called green cars not only because they are usually electric, but also because engineers are making the vehicles more efficient by making some driving decisions and reducing the time spent at stops and traffic lights.

In current AV technology, ACC is an automatic function that can improve driving comfort and safety by improving longitudinal vehicle control. Recently, some studies have begun to focus on how to make vehicles make energy-saving ACC strategies. Zlocki and Themann used vehicle simulation models to quantify the fuel reduction potential of ACC-related driving strategies in vehicles with different powertrains. This study showed through simulation tests and simple road tests that ACC technology can lead to fuel reduction, although the comprehensive range of road grades, traffic and other driving conditions was not evaluated. Mersky and Samaras developed a new fuel economy test method considering AV technology, which simulated different AV car following strategies to estimate the changes in fuel economy and concluded that efficiency-centered control strategies can improve fuel economy by about 10% (although AV-Featu does not guarantee fuel economy benefits from renewable energy).

Recently, Volvo also published a similar article in the IEEE Intelligent Transportation Systems Magazine, titled An Automated Vehicle Fuel Economy Benefits Framework Using Real-World Travel and Traffic Data (reply "ACC Energy Saving" to download the paper), which is a joint project between NREL and Volvo Car Corporation. The study uses real vehicle driving data to explore the impact of vehicle automation on fuel consumption. It has developed a fuel impact analysis framework and applied it to evaluate the potential impact of ACC operation. The study shows that compared with human drivers, the fuel consumption of automobile adaptive cruise control systems is reduced by 5-7%.

Despite the good conclusions, this study has several shortcomings:

1. Whether the interaction between ACC vehicles can lead to energy savings has not been studied. When the penetration rate of ACC functions increases, there will be interactions between multiple smart cars, which requires further measurement.

2. On the other hand, only fuel vehicles are considered, and there is a lack of sufficient data for vehicles such as hybrid or plug-in electric vehicles.

The large-scale field test data collected in the study all came from Volvo's "Drive Me" project, which is an autonomous driving project launched by Volvo Car Corporation in 2013. Volvo announced the launch of a large-scale autonomous driving test project with the aim of using technical means to solve some problems that may be encountered in actual traffic, such as traffic jams, fatigue, and difficulty in parking.

After the launch of the Drive Me project, it has been running in Gothenburg. In April 2016, Volvo announced that it would introduce the Drive Me autonomous driving project to China, but the Chinese government just stopped the high-speed test. Since then, the Drive Me project has not been exposed much. From the research direction this time, it can be seen that Volvo is still focusing on ADAS functions for mass production and gradually evolving towards autonomous driving.