Recommended Protocols for Developing Crash Modification Factors.

摘要

The topic of highway safety is an increasingly important issue in the field of transportation engineering. In past years, state and local transportation agencies would delegate safety responsibilities on an informal basis to various staff members. However, now it is not uncommon to find clearly defined safety units in these agencies. Whereas the primary focus used to be on moving vehicles through the roadway network most efficiently, now many departments are recognizing the need to address safety at multiple levels – planning, design, operations, and maintenance. Funding and influence from the federal level spurred the development of state Strategic Highway Safety Plans (SHSP), the strategies of which are carried out through efforts such as the Highway Safety Improvement Program (HSIP). Recently, state agencies through AASHTO coordinated with the Federal Highway Administration to decide on a national highway safety vision of zero deaths (http://safety.fhwa.dot.gov/tzd). Not only is safety becoming recognized as a critical issue, indeed the science of highway safety is moving forward. In past decades, engineers working to improve safety on their highways had to rely on engineering judgment alone to decide where to install countermeasures, which countermeasures were most appropriate, and how effective each countermeasure would be in reducing crashes. Resources to guide them were rare, as were quality research studies on safety issues and the effectiveness of countermeasures. Since then, the field of highway safety has progressed and expanded. There is a recognized need for safety decisions to be driven by good quality data. Studies from universities, research centers, and departments of transportation have begun producing a multitude of quantitative estimates of crash effectiveness of countermeasures. Research topics have been developed and ushered into funded studies through groups such as the Transportation Research Board committees. The science of highway safety took a major step forward in 2010 with the release of the first edition of the AASHTO Highway Safety Manual (HSM), which documented the state of knowledge regarding road safety management, predictive crash modeling, and countermeasure effectiveness in the form of crash modification factors (CMFs). Another resource came to the field in 2009 with the launch of the FHWA Crash Modification Factors Clearinghouse, which presents an online repository of CMFs.