SIMULATION-BASED PERFORMANCE EVALUATION FOR SMART ROAD SYSTEMS

GRANÀ, Anna; MACIOSZEK, Elżbieta; TUMMINELLO, Maria Luisa · 2025 · Crossref

DOI: 10.20858/sjsutst.2025.127.6

archive: archived pipeline: cataloged verified

Get this paper ↗ (DOI — opens at the source; we link to it, we don't host it)

Summary

This paper addresses the operational efficiency and safety of roundabouts within smart road systems, specifically examining the impact of increasing market penetration of connected and autonomous vehicles (CAVs). As autonomous driving technologies advance, integrating human-driven vehicles (HVs) with CAVs in complex intersections like multi-lane roundabouts presents significant challenges. The study aims to evaluate how varying proportions of CAVs affect traffic dynamics, including capacity, delay, travel times, and safety conflicts, thereby providing insights for optimizing roundabout design and management in the context of intelligent mobility. The researchers employed a microsimulation-based methodology using Aimsun software to model two roundabout case studies located in Sicily, Italy: a single-lane roundabout (Roundabout 1) and a two-lane roundabout (Roundabout 2). Geometric and traffic data were collected through camera monitoring and manual counts during peak hours. The study categorized entry lane types and developed benchmark capacity functions adjusted for cooperative adaptive cruise control. The simulation setup replicated real-world traffic demand and tested six market penetration percentages (MPPs) of CAVs, ranging from 0% to 100%. Model calibration involved sensitivity analysis and manual adjustment of parameters such as reaction time, safety margins, and acceleration to ensure simulated outputs aligned with benchmark data. Safety analysis was conducted using the Surrogate Safety Assessment Model (SSAM), evaluating conflicts based on time-to-collision and post-encroachment time thresholds. The results indicate that higher CAV penetration significantly improves operational efficiency. At Roundabout 1, entry capacity increased by up to 27.92% with 100% CAVs compared to the HV-only baseline. Similarly, Roundabout 2 saw capacity increases of up to 28.71% in the left entry lane and 24.73% in the right entry lane at full CAV penetration. These gains were driven by CAVs’ ability to accept shorter gaps and exhibit shorter reaction times. Consequently, delays and travel times decreased; for instance, at 60% CAV penetration, delays at Roundabout 1 dropped by approximately 13.45%. However, safety analysis revealed that total conflict rates increased with higher CAV proportions due to intensified competition for gap utilization. Notably, the two-lane roundabout exhibited a significant percentage of lane-change conflicts, attributed to the assertive driving behavior modeled for CAVs in the left lane. The study concludes that while CAV integration offers clear operational advantages in terms of capacity and reduced delays, it introduces safety complexities, particularly in multi-lane configurations. The findings highlight the need for careful calibration of CAV behavioral assumptions, such as assertiveness and gap acceptance, to balance efficiency with safety. The authors suggest that dedicated CAV lanes or turbo roundabout designs may mitigate safety concerns in mixed traffic. Future research should focus on validating these simulation assumptions with independent traffic data and exploring interdisciplinary solutions to optimize lane configurations and traffic control for seamless integration of cooperative driving technologies.

Provenance

The full processing record for this entry. Every stage of this paper's journey through the pipeline is logged — what ran, with which tool and model, how many attempts it took, and when it last completed.

Summary generated by qwen3.6-27b-prismaquant on 2026-06-26; verification: verified.

Topics

Ranked by relevance to this paper. Hover a topic for its definition.

• intersection design