From Lagging to Leading: Validating Hard Braking Events as High-Density Indicators of Segment Crash Risk

📅 2026-01-09
🏛️ arXiv.org
📈 Citations: 0
Influential: 0
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🤖 AI Summary
This study addresses the limitations of traditional crash data—sparse and lagging—which hinder high-precision prediction of segment-level crash risk. The authors propose using hard braking events (HBEs) from connected vehicles as a high-density surrogate safety measure and, for the first time, systematically validate their strong positive correlation with segment crash rates across a large-scale road network. Leveraging anonymized HBE data from Google Android Auto, they develop a negative binomial regression model incorporating covariates such as road type, speed distribution, distance to ramps, and grade to predict collision risk at the segment level. Empirical results demonstrate that HBE frequency is significantly higher than crash frequency and highly correlated with it, establishing HBEs as a scalable, forward-looking metric for proactive safety assessment, enabling timely interventions and safer route optimization.

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📝 Abstract
Identifying high crash risk road segments and accurately predicting crash incidence is fundamental to implementing effective safety countermeasures. While collision data inherently reflects risk, the infrequency and inconsistent reporting of crashes present a major challenge to robust risk prediction models. The proliferation of connected vehicle technology offers a promising avenue to leverage high-density safety metrics for enhanced crash forecasting. A Hard-Braking Event (HBE), interpreted as an evasive maneuver, functions as a potent proxy for elevated driving risk due to its demonstrable correlation with underlying crash causal factors. Crucially, HBE data is significantly more readily available across the entire road network than conventional collision records. This study systematically evaluated the correlation at individual road segment level between police-reported collisions and aggregated and anonymized HBEs identified via the Google Android Auto platform, utilizing datasets from California and Virginia. Empirical evidence revealed that HBEs occur at a rate magnitudes higher than traffic crashes. Employing the state-of-the-practice Negative-Binomial regression models, the analysis established a statistically significant positive correlation between the HBE rate and the crash rate: road segments exhibiting a higher frequency of HBEs were consistently associated with a greater incidence of crashes. This sophisticated model incorporated and controlled for various confounding factors, including road type, speed profile, proximity to ramps, and road segment slope. The HBEs derived from connected vehicle technology thus provide a scalable, high-density safety surrogate metric for network-wide traffic safety assessment, with the potential to optimize safer routing recommendations and inform the strategic deployment of active safety countermeasures.
Problem

Research questions and friction points this paper is trying to address.

crash risk prediction
high-risk road segments
safety surrogate metrics
collision data limitations
traffic safety assessment
Innovation

Methods, ideas, or system contributions that make the work stand out.

Hard-Braking Events
Connected Vehicle Technology
Crash Risk Prediction
Safety Surrogate Metric
Negative-Binomial Regression
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