1 INTRODUCTION

Crash test evaluations of roadside hardware have long been recognized as an initial assessment of hardware performance. The proper installation and maintenance of roadside hardware allows for the hardware to perform as designed and evaluated when impacted within the performance limits of the hardware. An In-Service Performance Evaluation (ISPE) documents how safety features perform within a broad range of collisions and real-world conditions, such as environmental, operations, and maintenance situations [1]. It is recognized that these conditions can vary widely from the conditions under which the hardware is crash tested.

“The objective of an in-service performance evaluation is to assess the crashworthiness of safety features under field conditions. A secondary objective is to determine which factors are influencing performance (e.g., maintenance, installation, hardware design, etc.). Consistent with the crash test evaluation criteria in MASH, safety feature performance is assessed through consideration of (1) structural adequacy, (2) occupant risk, and (3) vehicle trajectory with the greatest consideration being given to occupant risk” [2].

ISPEs have long been recognized as a desirable hardware evaluation step. Bronstad and Michie observed, within NCHRP Report 153 in 1974, that “the final evaluation of an appurtenance must be based on carefully documented in-service use” [3]. Likewise, Ross et al. observed within NCHRP Report 350 in 1993, that “in-service evaluation is the final and key step … to determine and document the manner in which the safety feature performs during a broad range of collision, environmental, operational, and maintenance situations for typical site and traffic conditions” [4].

An ISPE has several major phases: planning, data collection, data assembly, data analysis, and making recommendations and decisions based on the observed performance. This research effort addresses the second (i.e., data collection) and third (i.e., database assembly) phases. The planning, data analysis, and recommendations are addressed under NCHRP Research Report 1010: In-Service Performance Evaluation: Guidelines for the Assembly and Analysis of Data and NCHRP Web-Only Document 322: Multi-State In-Service Performance Evaluations of Roadside Safety Hardware [2, 5]. The data available within already collected crash databases are paramount for the successful conduct of an ISPE. An inventory is not necessary to conduct an ISPE. Transportation agencies, however, may find it beneficial to maintain an inventory of roadside hardware to monitor the field performance of roadside hardware and to address more complex questions. Creating an inventory of roadside hardware provides data that supplements the already available crash data.

Transportation agencies can effectively improve their understanding of roadside hardware field performance through the conduct of individual ISPEs, the institutionalization of ISPE programs, or as part of their agency asset management program:

• Individual ISPEs can be initiated using available crash data. Based on the outcome of the review of the available crash data, transportation agencies may choose to conduct an investigative ISPE which may involve reviewing field crashes as they occur to further separate performance success and concerns.
• ISPE programs may involve continuous monitoring and documenting of in-service crashes accompanied by the scheduled analysis and documentation of ISPE reports.

• Asset management is “a strategic and systematic process of operating, maintaining, and improving physical assets, with a focus on both engineering and economic analysis ….” [6]. Expanding the data collected under an asset management program could be used to support individual ISPEs and ISPE programs. These data may range from asset identification to the history of the asset at each particular location.

Effective data collection procedures and accurate execution of those procedures is necessary to support investigative ISPEs, ISPE programs, and to expand existing asset management programs to include roadside hardware. Effective data collection procedures will support a meaningful assessment of the condition and performance of roadside hardware.

The objective of this research is to develop a transportation agency data collection methodology and associated guidelines to support individual investigative ISPEs, ISPE Programs, and asset management of roadside safety hardware. This report documents the research undertaken to support the objective.

In the context of performing an ISPE, these terms are defined and used consistently to foster collective understanding:

• Data collection techniques are any methods that involve making measurements or observations of roadside hardware and features in the field. Data collection may be conducted on an ongoing basis, periodically, or on an as needed basis.
• Data collection procedures are the documented standardized practices for conducting a data collection activity and extracting and documenting the ISPE dataset.
• Data extraction and documentation of the collected data is the translation of the data relevant to the ISPE for incorporation in an ISPE dataset.
• Performance Evaluation is based upon the ISPE dataset using the analysis techniques for assessing hardware performance outlined in NCHRP Research Report 1010 [2].

ISPE data elements, sources, collection techniques, as well as extraction and documentation techniques were reviewed to develop the “Guidelines for the Collection, Extraction, and Documentation of Data” presented in Appendix A. Available procedures for the analysis of collected ISPE data were also reviewed. A summary of these reviews is included in this report. This report also includes a summary of the pilot test conducted using the developed procedures.

Appendix A provides a comprehensive, stand-alone document “In-Service Performance Evaluation: Guidelines for the Collection, Extraction, and Documentation of Data” also referred to as the “ISPE Data Collection Procedures Manual.” The manual incorporates data survey techniques as well as information on data extraction, documentation, and linking. Guidelines are presented for the development of an ISPE dataset, including desirable data elements and standardized naming and storage conventions which can be used consistently across transportation agencies.