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62 5.4.4 Summary of Findings and size and the PSUs to be included in the data collection effort Recommendations is merely a question of available funding. The following is a summary of findings and recommenda- tions gleaned from the pilot study: 5.5.2 Data Collection Forms The proposed data collection forms and procedures for the The study clearly demonstrated the feasibility of incorpo- continuous sampling subsystem are similar to those used in rating a long-term data collection effort on ran-off-road the current effort and the pilot study, but with some enhance- crashes into the existing NASS CDS program. However, ments based on experience gained in this study, including: note that the study included only the continuous data col- lection subsystem. Thus, the study results would not apply Supplemental Highway Data Collection Form to the special study subsystem. Object Struck Data Collection Form: It took an average of 135 minutes per case for the supple- Barrier mental data collection effort, consisting of 95 minutes at Crash Cushion the PSU level and 40 minutes at the Zone Center level. Embankment Furthermore, it is reasonable to expect that the time would Pole Support decrease slightly once the researchers are trained and become Tree familiar with the data elements and procedures. Other Struck Object There were no major issues of concern regarding the data Reconstruction Coding Form: collection or reconstruction of the cases. First Harmful Event Subsequent Harmful Event 5.5 Data Collection Protocol-- Performance Assessment Form Continuous Sampling Subsystem Scene Photographs The data collection protocol for the proposed continuous Copies of these proposed data collection forms and the cor- sampling subsystem is essentially unchanged from that of responding coding and field procedures manuals are included the current retrospective study or the pilot study. Detailed in Appendix F. descriptions of the data collection protocol are provided pre- viously in Chapter 1 and Section 5.4 and will not be repeated herein. Only the highlights of the data collection protocol are 5.5.3 Organization summarized in this section. The data collection effort is best sponsored by AASHTO and administered through NCHRP. An outside contractor would be hired to conduct the study and to coordinate the 5.5.1 Sampling Plan data collection effort with NASS. A project panel, or a tech- The cases for the continuous sampling subsystem would be nical advisory committee composed of management-level selected from within the NASS CDS sample, using the same personnel from the sponsoring agency and NASS, would notification system. The sampling criteria may include, but oversee the overall conduct of the study, provide guidance are not limited to, the following: and direction to the contractor, and review the study progress and results. Area type--rural and suburban If only the continuous sampling subsystem is to be imple- Single-vehicle, ran-off-road crashes mented, then the most logical and cost-effective arrangement Passenger-type vehicles only--passenger cars and light is for the field data to be collected by existing NASS inves- trucks tigators and quality controlled by Zone Center personnel, Speed limit 75 km/h (45 mph) assuming the additional work load would not adversely affect the regular CDS operation. Based on previous experience The actual sampling criteria used may vary, depending with the retrospective studies, the additional time required to on the specific questions to be addressed with the data. For collect and code the supplemental field data is estimated to be example, the area type may be expanded to include urban no more than two hours per case. For a given PSU, the num- areas with speed limits of 65 km/h (40 mph) and slower, or ber of eligible cases is likely to be less than 50 per year. Thus, the vehicle type may be expanded to include single-unit the additional time devoted to the supplemental data collec- trucks and tractor-trailers, depending on the questions to be tion would not be more than 100 hours per year per PSU, or addressed in the study. On the other hand, the actual sample less than two hours per week per PSU. It is evident from the