Proposed Empirical Approach to Measuring Traffic String Stability

Proposed Empirical Approach to Measuring Traffic String Stability

Raju, Narayana (TU Delft Transport and Planning)
Patil, Shubham (Sardar Vallabhbhai National Institute of Technology)
Arkatkar, Shriniwas S. (Sardar Vallabhbhai National Institute of Technology)
Easa, Said (Ryerson University)

2022

This study originated with the intent of qualifying traffic string stability from empirical observations. A new responsiveness angle measure was developed to assess driver instincts under vehicle-following conditions. In this measure, the degree of the follower vehicle's attention towards its leader vehicle's actions is quantified. In understanding string stability in the traffic stream and assessing the propagation of disturbances, the newly conceptualized measure was used along with a discrete Fourier transform to measure the frequencies associated with responsiveness angle sequences. In this transform, a higher frequency of the angle depicts unstable conditions and vice versa. In assessing string stability from the empirical observations, vehicular trajectory data were developed from three study sections. Two study sections tended to have homogeneous lane-wise traffic, whereas the third section had mixed (heterogeneous) traffic. The results of the string stability analysis over the study sections showed that string stability varied with the change in traffic flow conditions, road geometries, and traffic flow type. In the case of free-flow conditions, the traffic streams were found to be stable with marginal disturbances in the responsiveness angle. From the analysis, it was observed that, in the case of study Section 3, around 26 instances of the stream were extremely unstable conditions (frequency equal to 10). For study Sections 1 and 2, the traffic stream was unsteady for 4 and 13 instances, respectively. However, as the traffic flow level rose, string stability deteriorated. This study demonstrated a novel approach to analyzing string stability based on actual traffic conditions that can be implemented in real time for traffic stream monitoring.

Traffic string stability
Real-time management
Trajectory data
Driver attention

http://resolver.tudelft.nl/uuid:6b9ee96c-7466-45d3-a700-219725f99da1

https://doi.org/10.1061/AJRUA6.0001227

2022-07-27

2376-7642

ASCE-ASME Journal of Risk and Uncertainty in Engineering Systems, Part A: Civil Engineering, 8 (2)

Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.

Institutional Repository

journal article

© 2022 Narayana Raju, Shubham Patil, Shriniwas S. Arkatkar, Said Easa