Guidance to Improve Pedestrian and Bicyclist Safety at Intersections (2020)

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97 GUIDANCE TO IMPROVE PEDESTRIAN AND BICYCLIST SAFETY AT INTERSECTIONS Chapter 7: Conclusions and Epilogue This Guide provides a comprehensive, high-level process for countermeasure selection, moving from framing the project, through data collection and analysis, and into initial countermeasure selection and refinement based on project context and constraints. Supplementary materials in the Countermeasure Glossary support this work, as do resources cited throughout this Guide, such as PEDSAFE, BIKESAFE, CMF Clearinghouse, and AASHTO’s Guide for the Planning, Design, and Operation of Pedestrian Facilities (2004) and Guide for the Development of Bicycle Facilities (2009). While not a part of the countermeasure selection process, an important part of planning and engineering is evaluating the success of the chosen countermeasures. This is particularly important for newer or unproven countermeasures, and is the reason the profession can point with confidence to certain well-established countermeasures. Evaluations can range from fairly simple to complex. Often, they are conducted by comparing crashes before and after countermeasure installation. However, this type of simple evaluation may result in misleading conclusions, given the way that crashes naturally fluctuate over time and place. Thus, this Guide recommends a more robust evaluation that includes at least 2 years of data captured before and after implementation and both the test sites and the comparison sites. For jurisdictions with the resources, the gold standard is to examine at least 3 years of both “before” and “after” data at multiple test and control sites that otherwise have similar characteristics. Because waiting 3 years after implementation to evaluate a countermeasure can be difficult, some studies employ noncrash data such as severe conflicts (also known as “near misses”), driver yielding rates, observed speed, or other observed behavior as surrogate measures of safety. The CMF Clearinghouse provides useful resources on performing robust countermeasure evaluations (Carter et al. 2012, Gross et al. 2010), though care should always be taken to select appropriate CMFs. Emerging sensor technologies and crowdsourced information (e.g., from driver cell phone applications) may also provide helpful shorter-term data that are available in large enough amounts to provide insights into the effectiveness of the implemented treatments. Occasionally, surveys of public awareness or behavior are also conducted, although reported behavior may not match actual behavior. Even if a jurisdiction does not have the resources to perform a robust in-house evaluation, it can still be advantageous to collect the needed data so that others can perform these evaluations. Whenever possible, important data to collect for evaluation include: • Traffic volumes for pedestrians, bicyclists, and motor vehicles before and after countermeasure installation. • Numbers of crashes by pedestrian and bicycle crash type. • List of dates and locations when countermeasures were installed. The field of countermeasure development continues to evolve as new needs are discovered and new technologies emerge. Working together to share the lessons learned from evaluation, as well as sharing data that contribute to a greater understanding of countermeasure effectiveness, will further enhance the profession and, most importantly, the safety of the most vulnerable roadway users.