Guidance-oriented advanced curve speed warning system in a connected vehicle environment

Area of Science:

• Road safety engineering
• Intelligent transportation systems
• Human factors in driving

Background:

• Existing highway curve warning systems often fail to ensure consistent speed compliance.
• Drivers may adjust speed before curves but not maintain it within the curve.
• A need exists for continuous guidance throughout the entire curve navigation process.

Purpose of the Study:

• To develop and evaluate an Advanced Curve Speed Warning (Advanced-CSW) system.
• To improve driver speed compliance on horizontal curves using continuous, guided messages.
• To leverage Dedicated Short-Range Communication (DSRC) for vehicle-infrastructure (V2I) interaction.

Main Methods:

• A driving simulator study with 30 participants navigating curves under various conditions (severity, illumination, wetness).
• Implementation of the Advanced-CSW system providing real-time, in-vehicle speed guidance.
• Evaluation of speed difference between in-curve speed and advisory speed, compared to traditional systems (CSW, CSO).
• Statistical analysis using mixed-effects linear models to account for individual driving behavior.

Main Results:

• Advanced-CSW significantly increased speed compliance for male drivers compared to one-time warnings or curve signs only.
• Male drivers using Advanced-CSW showed significantly reduced speed differences (6.53–7.68 mi/h).
• Female drivers showed improved compliance with curve signs only, compared to one-time or continuous guided messages.
• Continuous guided messages during daytime reduced male drivers' speed by 1.81 mi/h compared to nighttime.

Conclusions:

• The proposed Advanced-CSW system effectively enhances speed compliance on highway curves, particularly for male drivers.
• Continuous, adaptive speed guidance throughout the curve navigation is superior to existing warning methods.
• Future curve warning systems should incorporate real-time speed and location adaptive guidance.