Balancing Safety, Stability, and Comfort in Semi-Truck Platooning: A Study on Safe and Optimal Headways under Real-World Traffic Conditions

On highways, platoons of semi-trucks are a common phenomenon. By maintaining a small headway, these platoons can effectively reduce air resistance, thereby improving fuel efficiency and reducing carbon emissions. However, this driving mode is also accompanied by many safety and operational risks, such as increased risk of rear-end collisions, reduced driving comfort, and susceptibility to interference from other vehicles outside the platoon. Therefore, behavioral analysis and evaluation of semi-truck platoons naturally formed in real traffic environments are of great significance for improving their driving safety, comfort and stability. This study focuses on the headway characteristics of semi-truck platoons, analyzes their headway distribution, headway gap and braking response behavior, and then proposes a safe headway threshold for emergency braking to effectively reduce the probability of rear-end collisions. In addition, the study also defines an optimal headway range to reduce the possibility of external vehicle insertion, thereby improving the overall stability and driving experience of the platoon. Based on this, this paper constructs a semi-truck platoon model with safety as the core, and verifies it with actual traffic data, revealing the behavioral characteristics of naturally formed semi-truck platoons in terms of safety headways, optimal headways, and platoon distributions. The research results not only provide theoretical support for improving the safety and stable operation of naturally formed truck platoons, but also provide technical reference for the deployment and operation of future connected and automated truck (CAT) platoons in real road environments, helping the freight industry to develop in a more efficient and sustainable direction.