چارچوبی برای نظارت بر شبکه ایمنی ترافیک سطح راه
Abstract
1- Introduction
2- Methodology
3- Implementation
4- Results
5- Conclusions and recommendations
Acknowledgments
Appendix A. Supplementary material
References
Abstract
Currently, there are both methodological and practical barriers that together preclude the use of theoretically sound approaches for network screening as part of a traffic safety management process. Methodological barriers include, among others, lack of a comprehensive framework for corridor-level network screening. Existing corridor screening methodologies use observed crash frequency as a performance measure. In practice, corridorlevel screening is extremely important because traffic safety engineers prefer to deploy countermeasures and provide homogenous conditions throughout corridors to meet drivers’ expectations and avoid confusion. On the other hand, practical barriers that limit the use of sound approaches for traffic safety include (1) significant data integration requirements, (2) a particular data schema is needed to enable analysis using specialized software, (3) time-consuming and intensive processes are involved, (4) substantial technical knowledge is needed, (5) visualization capabilities are limited, and (6) coordination across various data owners is required. This research proposes a systematic methodology for corridor-level network screening. The solution algorithm is implemented within a Business Intelligence (BI) platform to address, to the extent possible, the practical barriers listed above. BI provides methods and mechanisms to integrate and process data, generate advanced analytics, and visualize results by using intuitive and interactive web-based dashboards and maps. Experiments and results illustrate the advantage of using the proposed framework for corridor-level network screening implemented within a BI platform.
Introduction
Ensuring traffic safety is the focus of such federal legislation as the Transportation Equity Act for the 21st Century (TEA-21), the Safe Accountable Flexible and Efficient Transportation Equity Act - A Legacy for Users (SAFETEA-LU), and the Moving Ahead for Progress in the 21st Century (MAP-21). SAFETEA-LU and MAP-21 both require that states develop comprehensive Highway Safety Improvement Plans (HSIPs) (FHWA, 2013). One of the critical programs of HSIPs is the traffic safety management process, which involves annual reporting of the highway locations that exhibit the most severe traffic safety needs. By identifying the most hazardous roadway site locations, specific countermeasures can be implemented to improve safety conditions. In a traffic safety management process, identifying locations with the potential for safety improvements is known as network screening. Network screening is critical because a detailed engineering study for all network sites is expensive. The purpose of network screening is to review the entire roadway network, or portions, and identify and prioritize corridors and sites with potential for safety improvements. These identified corridors are recommended for further investigation and a detailed safety engineering study.
For network screening, despite the availability of approaches such as the Empirical Bayes (EB) method recommended by the Highway Safety Manual (HSM) (AASHTO, 2010) and those that deal with unobserved heterogeneity (Mannering et al., 2016; Mannering, 2018), practitioners continue using very simplistic methodologies which rely only on observed crash frequency or crash rates. For HSIP reports submitted to the Federal Highway Administration in fiscal year 2014, only four states used the EB for network screening as described in the HSM (FHWA, 2015).