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16 CHAPTER 4 Prioritization of Strategies The follow-up interviews discussed in the previous chapter Extent of the coverage in previous/ongoing work. Task 1 revealed many problems with using data from many of the (literature review) indicated if a particular strategy has been agencies. Some of the difficulties uncovered during the rigorously evaluated by previous work or is being evaluated follow-up interviews included: in another ongoing study, and the quality and predictive certainty of the CMFs developed so far. Lack of resources to participate in an evaluation. Importance to the user. In order for the results of this study Unable or unwilling to participate in this study. to be successfully implemented, it needs to focus on strate- Inadequacies in crash data. gies that are important to the end user. Results of Task 2 No electronic crash data (i.e., crash reports are only (i.e., the importance as identified by the survey respondents) available in paper copies). were used to determine the importance of the strategies to Recent historical data (i.e., older than 3 years) are not the end user. available. Data assessment. The objective was to identify databases Crash data cannot be linked to intersections. and determine the quality and quantity of data available for Installation records for the strategy were not available. the development of high-quality CMFs using a rigorous The strategy was installed at the same time the road was before/after study. Phone interviews were conducted of built (therefore, there is no before data for a before-after respondents who potentially had data as part of Task 2 in evaluation). order to make a preliminary assessment of this factor. The Lack of data for reference group intersections. intent was to identify agencies that can provide data for Inadequacies in supporting data. multiple treatments and thereby reduce data collection costs. No volume data. Ability to identify crash effects. Strategies that may lead to No historical volume data. diversion of traffic and/or have a system-wide effect would No inventory data. require more extensive and cost-prohibitive data collection Other improvements were made at the same time. efforts. Similarly, treatments that may have a small effect Changes have been made since installation. on total crashes may require a relatively large sample of sites to conduct a cost-effective evaluation. Based on the outcomes of the interviews, a prioritized list of strategies for evaluation along with a work plan was submitted Based on these criteria and on the available budget, three to the NCHRP Panel as part of the Interim Report. In devel- treatments were identified for evaluation: oping the list of prioritized strategies, tried, experimental, and proven strategies (based on NCHRP Report 500, Volume 12) Adding protection for left-turning vehicles which includes were considered. The original solicitation had indicated that the following treatments: the focus should be on tried and experimental strategies. Introduce protected left-turn phasing. However, comments from the panel members on the quar- Introduce permissive-protected or protected-permissive terly progress reports indicated that proven strategies should left-turn phasing. be considered as well. Modify left-turn phasing and add left-turn lane at the The prioritized list of strategies was developed after con- same time. sidering the following: Lengthen left-turn lanes.