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1  The Highway Safety Improvement Program (HSIP) is a core federal-aid highway program with the purpose of achieving significant reductions in fatalities and serious injuries on all public roads. Although there are federal requirements that guide state HSIP efforts, there are several variations in how state departments of transportation (DOTs) identify, prioritize, and evaluate HSIP projects. It is important to understand these variations and opportunities to improve current practice because every phase of the HSIP, from project identification to evaluation, has the potential to impact the safety performance of current or future projects. State DOTs can maximize the effectiveness of the HSIP by employing sound safety manage- ment approaches, economic measures, implementation strategies, and professional judgment. The objective of this synthesis is to document current state DOT practices for identifying, prioritizing, and evaluating HSIP projects. To accomplish this objective, this study employed a multifaceted approach, including a literature review, a survey of state DOT safety programs, and a series of interviews with state DOT personnel. The literature review included a review of 36 state HSIP and safety program manuals along with state HSIP annual reports and other federal and state resources that describe methods to identify, prioritize, and evaluate HSIP projects. The survey consisted of 24 questions and was sent to the HSIP annual report con- tact person in all 50 states, the District of Columbia, and Puerto Rico, with a response rate of approximately 85%. In-depth interviews focused on four state DOTs to serve as diverse case examples with respect to practices on state and local roads as well as spot, systemic, and systematic approaches to safety management. The results of the literature review and survey are consistent, which helps to validate the information obtained from both sources. The following are key takeaways related to each area (project identification, prioritization, and evaluation). Project Identification ⢠The process to identify, prioritize, and evaluate spot HSIP projects is well established, as evidenced by the HSIP documentation in most state DOTs. ⢠There are fewer state DOTs with a documented approach to systemic HSIP projects. ⢠A limited number of state HSIP manuals include a documented approach on how to identify systematic projects. ⢠Traditional network screening performance measures (e.g., crash frequency and crash rate) are most common for spot projects, but there are several state DOTs that have implemented more rigorous and contemporary methods from the Highway Safety Manual (HSM) [e.g., level of service of safety (LOSS), excess predicted crashes, expected crashes, and excess expected crashes]. S U M M A R Y Practices for Balancing Safety Investments in a Comprehensive Safety Program
2 Practices for Balancing Safety Investments in a Comprehensive Safety Program ⢠Systemic methods range from basic to advanced, with most state DOTs using more basic approaches to systemic analysis. ⢠Nearly all state DOTs use more in-depth investigations to diagnose the crash patterns and underlying crash contributing factors, particularly for potential spot project locations. ⢠Diagnostic methods for spot locations range from basic crash summaries and collision dia- grams to the tests of proportions and multidisciplinary site investigation teams. ⢠Some state DOTs provide further guidance and resources for countermeasure selection, including an approved list of countermeasures and a list of applicable crash modification factors (CMFs) for use in benefit-cost analysis. ⢠For both spot and systemic approaches, most state DOTs use the same method to identify potential projects on state and local roads. ⢠Many state DOTs supplement quantitative approaches with qualitative input from stake- holders (e.g., public inputs, police requests, or observations by district or regional staff) to identify potential project locations. Project Prioritization and Funding Allocation ⢠The most common quantitative approach to project prioritization is the benefit-cost ratio. ⢠Most state DOTs that compute the benefit-cost ratio base the estimate on expected reduc- tions in total crashes. ⢠Some state DOTs use variations such as benefits based on expected reductions in fatal and serious injury crashes. ⢠Many state DOTs incorporate one or more qualitative or non-crash-based factors to prioritize projects. ⢠Some state DOTs prioritize all candidate projects together, and some have set-aside funding for state and local projects, spot and systemic projects, or specific emphasis areas (e.g., road- way departure, intersection, pedestrian, bicycle). ⢠Some state DOTs split funding between spot and systemic projects or state and local projects, but few of the reviewed state DOTs have a formula to allocate funding between these projects. ⢠The most common quantitative approaches to allocating funding are based on the distri- bution of fatal and serious injury crashes. ⢠Other state DOTs have established funding allocation goals based on qualitative assess- ments and professional judgment. Project Evaluation ⢠State DOT guidance on project evaluations ranges from detailed procedures to acknowl- edgment of an evaluation process to no reference of evaluations at all. ⢠The simple beforeâafter study design without traffic volume correction is the most common project evaluation method. ⢠Relatively few state DOTs use anything more rigorous for project-level evaluations. ⢠Some state DOTs use more reliable methods to develop CMFs based on countermeasure- level evaluations. ⢠State DOTs typically evaluate all projects in a similar framework regardless of how the projects are identified or prioritized (e.g., spot versus systemic or state versus local road). Based on the results of the synthesis, there are opportunities to address gaps related to methods, data, and project implementation. The following are key opportunities for future research in these areas.
Summary 3  Methods ⢠Demonstrate the value of using more reliable methods throughout the HSIP process. ⢠Advance the state-of-the-practice on risk factor identification and project prioritization. ⢠Investigate the relative strengths and limitations of different funding allocation options. ⢠Increase the use of the predictive method, including the use of safety performance func- tions (SPFs) and CMFs in countermeasure selection and economic analysis. ⢠Market existing resources related to the use of the predictive method and other reliable methods for identifying and prioritizing countermeasures and projects. ⢠Develop guidance or training on how to estimate the expected safety benefits of systemic improvements. Data ⢠Address challenges related to data quality and maintenance over time. ⢠Provide access to data, as needed, for safety management purposes. Project Implementation ⢠Develop case studies and noteworthy practices on how to improve project implementa- tion, including the use of project bundling and indefinite delivery, indefinite quantity (IDIQ) contracting mechanisms.
