National Academies Press: OpenBook

Systemic Pedestrian Safety Analysis (2018)

Chapter:Chapter 8 - Step 7: Evaluate Program and Project Impacts

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Page 54
Suggested Citation:"Chapter 8 - Step 7: Evaluate Program and Project Impacts." National Academies of Sciences, Engineering, and Medicine. 2018. Systemic Pedestrian Safety Analysis. Washington, DC: The National Academies Press. doi: 10.17226/25255.
Page 55
Suggested Citation:"Chapter 8 - Step 7: Evaluate Program and Project Impacts." National Academies of Sciences, Engineering, and Medicine. 2018. Systemic Pedestrian Safety Analysis. Washington, DC: The National Academies Press. doi: 10.17226/25255.
Page 56
Suggested Citation:"Chapter 8 - Step 7: Evaluate Program and Project Impacts." National Academies of Sciences, Engineering, and Medicine. 2018. Systemic Pedestrian Safety Analysis. Washington, DC: The National Academies Press. doi: 10.17226/25255.

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54 Evaluation and monitoring is a key part of a systemic process. The purpose of this chapter is to describe the final step in the systemic process, which involves evaluating program and project impacts before starting the process anew. Evaluate Systemic Programs There are several actions that can be taken to judge the progress and outcomes of a systemic pedestrian safety program. Agencies may consider looking at various process measures to deter- mine if the systemic analysis and prioritization process have been implemented as planned. This could involve • Determining if each of the other six steps in the systemic process has been carried out; • Documenting what barriers to implementation arose and what additional measures are needed, such as data improvements, changes to policies or funding structures, training, addi- tional tools, coordination across agencies, and so on; and • Summarizing how many locations in the system were identified as high risk and what percent- age of the high risk locations had specific countermeasures recommended and implemented through the process. Going a step beyond process evaluation, systemic projects and their documentation may play a role in broader performance monitoring. This could involve examining the program not only from the safety perspective but also in terms of how it supports connectivity, reliability, and other pedestrian transportation goals. For example, many performance measures documented in FHWA’s Guidebook for Evaluating, Establishing, and Tracking Pedestrian and Bicycle Performance Measures (see Additional Resources) may be applicable to a systemic pedestrian safety program benchmarking. The FHWA guidebook describes measures at the local, metropolitan planning organization, state, and national level for tracking safety and other pedestrian transportation goals such as connectivity, mobility, health, and equity. These performance measures could be considered when evaluating a systemic program. Several specific aspects of the systemic program will also need evaluation and/or validation. Depending on the type of program initially established, the types of evaluation and program renewal activities may vary. For example, if an agency developed SPFs to use in risk identification and screening, there is likely a need to validate the risks identified in the model using engineering judgment. This type of validation could be accomplished through field investigations or road safety audits at sites having risk characteristics and may include observing conflicts and condi- tions at a sample of sites. C H A P T E R 8 Step 7: Evaluate Program and Project Impacts

Step 7: Evaluate Program and Project Impacts 55 If SPFs are used for ranking sites for systemic treatments, agencies may also wish to validate how well the model predicts, on average, where crashes occurred using updated data. If rankings are developed through other or expert weighting procedures, a similar assessment may be performed. Evaluate Systemic Projects Systemic projects and ideally all types of safety projects should be evaluated to determine the safety impacts. It is important to evaluate the impacts across all treatment sites where similar treatments were implemented, because crashes would be expected to be low at any one site. Again, if SPFs were developed for screening and ranking, these models could be used to pre- dict baseline expected crash rates for the facility and location types without the treatments to compare with effects with the treatment. However, given the average low propensity for crashes for many sites included in systemic projects, the potential effects on crashes may be difficult to detect unless data can be pooled for many sites and a number of years. State or regional agen- cies may be able to facilitate the development of robust evaluation data sets for both initial risk identification and evaluation, by pooling roadway and project data across several jurisdictions, thereby increasing potential for significant findings. There are also alternative measures of impacts that may be assessed in the shorter term. Mea- sures such as operating speed and other surrogate safety measures may indicate whether the treatments are working as expected. For example, if leading pedestrian intervals were imple- mented at signalized intersections, are pedestrians able to establish presence in the crosswalk before motorists begin turning? Are conflicts reduced? Do motorists yield? Are there certain locations where the treatments seem to work better than others? How do those locations differ? The use and efficacy of surrogate-based safety evaluations are areas of active research. Qualita- tive evaluations, including actively engaging the public to see how the new treatments are serving travelers’ needs and are being used, are also important. To make these program and project assessments, it is important to consider these needs before treatments are implemented so observations may be conducted before and after. Plan ahead so that the relevant types of observations for each treatment type, as well as the need for comparison locations, can be planned in conjunction with location and countermeasures selection. Renew Analyses At this point in time, there is no clear research-based guidance on the time frame for renewing SPF development or other risk analyses. Consider the extent of changes to the roadway network (including the systemic projects previously implemented), changes in traffic and pedestrian vol- umes and land use, or the availability of new and improved data to add to the analysis. Noteworthy Practice Since there was a need to better understand the risks associated with signalized intersections, Seattle DOT performed some additional field assessment and model validation activities after initial intersection SPFs were developed. Through this process, the agency also determined it would be valuable to collect additional data on turning movements and phases at intersections to help improve the next round of systemic analysis.

56 Systemic Pedestrian Safety Analysis Additional Resources Below are additional resources on pedestrian safety planning and management. Noteworthy Practice Seattle DOT made the decision to update SPF predictions with new data after 3 years using the same models. They planned to develop new SPF models, with new data, after 5 years. Resource Link FHWA’s How to Develop a Pedestrian and Bicycle Safety Action Plan fhwasa17050.pdf National Association of City Transportation Officials’ Urban Street Design Guide National Association of City Transportation Officials’ Urban Bikeway Design Guide FHWA’s Incorporating Safety into the Planning Process presentation120114.pdf FHWA’s Safety Focused Decision-Making Framework FHWA’s Applying Safety Data and Analysis to Performance–Based Transportation Planning

Next: Chapter 9 - Case Example 1: Seattle Department of Transportation »
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TRB's National Cooperative Highway Research Program (NCHRP) Research Report 893: Systemic Pedestrian Safety Analysis provides a safety analysis method that can be used to proactively identify sites for potential safety improvements based on specific risk factors for pedestrians. A systemic approach, as opposed to a “hot-spot” approach, enables transportation agencies to identify, prioritize, and select appropriate countermeasures for locations with a high risk of pedestrian-related crashes, even when crash occurrence data are sparse. The guidebook also provides important insights for the improvement of data collection and data management to better support systemic safety analyses.

The Contractor's Final Technical Report and a PowerPoint presentation summarizing the project accompany the report.

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