A Study on Driving Performance Along Horizontal Curves of Rural Roads

Calvi, Alessandro · 2014 · OpenAlex-citations

DOI: 10.1080/19439962.2014.952468

archive: archived pipeline: cataloged verified

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

Summary

This study investigates the impact of horizontal curve geometry on driving performance to address the elevated crash rates associated with rural road curves. Horizontal curves are statistically more dangerous than straight segments, often resulting in single-vehicle run-off-the-road accidents due to driver misperception of speed and curvature. The research aims to quantify how specific geometric features—radius, transition curves, visibility, and cross-section—affect driver behavior, thereby providing data to improve road safety design. The researchers conducted a multifactorial experiment using a fixed-based driving simulator at Roma Tre University. The final sample consisted of 30 licensed drivers (mean age 26.2 years) who navigated three distinct road scenarios: a narrow two-lane rural road, a wider two-lane rural road, and a divided highway. Each scenario included 24 horizontal curves, totaling 72 unique curve configurations. The study manipulated four independent variables: curve radius (sharp, medium, shallow), visibility (unrestricted vs. restricted by side slopes), presence of clothoid transition curves, and road configuration. Dependent measures included average driving speed, Pathologic Discomfort (PD), and Dispersion of Trajectory (DT). PD serves as a surrogate for safety by measuring the deviation of lateral acceleration from the theoretical value required by the road curvature, indicating excessive steering corrections. DT measures the variability of the vehicle’s lateral position within the lane. Data were analyzed using repeated measures ANOVA to assess main and interaction effects. The results demonstrated that curve geometry significantly influences driving performance metrics. Drivers adjusted their speeds and trajectories based on the specific combination of radius, visibility, and road width. The study confirmed that restricted visibility and sharper radii increased Pathologic Discomfort, indicating that drivers struggled to maintain a trajectory consistent with the road geometry, likely due to uncertainty and increased attentional demands. Similarly, Dispersion of Trajectory varied across conditions, reflecting difficulties in lane keeping under certain geometric constraints. The statistical analysis revealed significant main and interaction effects, showing that driver behavior is not determined by a single factor but by the complex interplay of visibility, radius, and cross-section. The findings underscore the validity of driving simulators as tools for evaluating the relationship between road design and driver behavior. By identifying how specific geometric features induce unsafe driving patterns, such as excessive steering corrections or lane position variability, the study provides empirical evidence for optimizing road infrastructure. The results suggest that improving visibility and adjusting curve radii and transition lengths can mitigate driver errors, ultimately reducing the high incidence of crashes on horizontal curves. This contributes to the development of safer, self-explaining road designs that align with driver perception and capabilities.

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.

• road geometry
• urban rural setting
• rail grade crossings
• perceptual countermeasures