Systemic Pedestrian Safety Analysis

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NCHRP Research Report 893 Systemic Pedestrian SafetyFinal Presentation Materials Presentation Overview Background.
Project Description Objectives Key Tasks and Findings Guidebook Overview Systemic Analysis Process.
Highlights of Guidebook Steps Conclusions Project Limitations and Considerations Future Research Needs Background.
Tenets of a Systemic Approach Identifies a safety concern based on an evaluation of data at thesystem or network level Establishes common characteristics risk factors of locations wheresevere crashes frequently occur.
Emphasizes low cost safety countermeasures to address the riskfactors identified Prioritizes locations across the entire roadway network where riskfactors are present regardless of prior crash history From FHWA s Systemic Safety Project Selection Tool Preston et al 2013 .
Background Project Description Guidebook Overview Conclusions Benefits of a Improved safety with moreproactive approach Don t simply chase the hot spots .
Informed decision making utilizesdata on key risk factors Optimized investment Cost effective use of resources Consistency in application.
Background Project Description Guidebook Overview Conclusions Key Takeaway Systemic ApproachDefinition A systemic approach is a data driven network wide or system level approach to identifying and treating high risk roadway features.
correlated with specific or severe crash types Systemic approachesseek not only to address locations with prior crash occurrence but alsothose locations with similar roadway or environmental crash riskcharacteristics Background Project Description Guidebook Overview Conclusions.
FHWA s Systemic Approach to Identifies focus crash types and risk Screens the network to identify locationswith relevant risks for treatment Identifies candidate countermeasures to.
address risks Prioritizes projects Identifies allocates funding Evaluates safety and other impacts ofsystemic projects.
Background Project Description Guidebook Overview Conclusions Why Do We Need a Systemic SafetyProcess Specific to Pedestrians Pedestrian crashes may be rare or widely dispersed across a network making a hot spot approach unreliable and cost ineffective in.
identifying and addressing pedestrian safety Crash risk factors for pedestrians are different than for motor vehicles and there is a need for specific guidance and research to augmentexisting tools and guides The process needs to be tailored to data related to pedestrians and.
to provide guidance on how to gather needed data Background Project Description Guidebook Overview Conclusions Project Description Project ObjectivesDevelop a process and Guidebook that includes .
1 Analytical methods to identify roadway features behaviors and othercontextual risk factors associated with pedestrian crashes2 Methods to identify appropriate and cost effective systemic pedestriansafety improvements to address the associated risk factors3 Information to enable transportation agencies to prioritize candidate.
locations for selected safety improvementsBackground Project Description Guidebook Overview Conclusions Key Project Tasks Phase 1 Review State of the Practice Conduct a literature review and interviews with practitioners.
Focus on differences and challenges for implementing an analytic systemic process for pedestrian safety Identify data needs and sources for a robust systemic pedestrian process Phase II Conduct Additional Research Compile risk factors associated with pedestrian crash frequency and or severity from published analyses Conduct original analysis to identify additional risk factors associated with two types of pedestrian.
midblock collisions Review and identify a select set of candidate pedestrian crash countermeasures compatible with systemic Phase III Develop Guidance Develop Guidebook on a systemic pedestrian safety process Develop and incorporate case studies describing real or hypothetical applications.
Background Project Description Guidebook Overview Conclusions Phase I Key Findings Some agencies misunderstood what a systemic approach entails While many agencies face data and other limitations there is highmotivation to collect and compile the needed types of data to.
perform more robust analyses to determine factors associated withpedestrian crash risk and develop reliable prioritization metrics There is an extensive body of pedestrian risk research that could bemined for potential use done in Phase II and incorporated intoGuidebook .
Background Project Description Guidebook Overview Conclusions Phase II Key Findings Analysis of two types of segment related midblock pedestriancollisions using network wide data was performed to Test an application of a systemic analysis.
Identify additional risk factors associated with segments Risks identified were incorporated into the Guidebook Applied results to illustrate identification and prioritization of sites Identified more than a dozen effective countermeasures feasible forsystemic application.
Background Project Description Guidebook Overview Conclusions Guidebook Overview Guidebook Elements Overview Background on a Systemic Process and key features.
How to use the Guidebook and intended audience Relation to other agency processes Process steps Examples Glossary of key terms.
Appendices Companion Final ReportBackground Project Description Guidebook Overview Conclusions Steps in theBackground Project Description Guidebook Overview Conclusions.
Step 1 Define Study Scope Purpose is to identifya problem type thataccounts for a large of the problem.
Typically only crashdata is used Uses descriptivemeans such as crashtree diagrams see.
NC example at right Background Project Description Guidebook Overview Conclusions Step 2 Compile Data Guidebook provides information and examples on how and why tomake data current and complete easily accessible centralized .
digitized linkable across databases and spatially referenced Recommended data for systemic analysis include Pedestrian crash records including injury severity crash type and spatialreferences Detailed roadway data with key characteristics such as of lanes.
Vehicle traffic and pedestrian volumes or secondary data to estimate volumes e g transit ridership population employment density etc Other measures of the built and social environmentBackground Project Description Guidebook Overview Conclusions Step 3 Identify Risk Factors.
Recommended approach Identify risk factors from regression modeling of jurisdiction wide data i e develop Safety Performance Functions or SPFs Alternative approaches Identify risk factors from prior research plus local judgment.
Infer risk factors from roadway and crash data frequency analysesBackground Project Description Guidebook Overview Conclusions Advantages of a Modeling SPF More reliable than other methods Accounts for crash randomness to identify sites with more than average risk.
Simultaneously accounts for multiple risk factors including activity exposure of people to vehicles Accounts for local context which may differ from where other risk factorstudies were developed Expedites subsequent steps in the process since data are already.
available for screening prioritization and application of SPFs Builds on the current best practice from the traffic engineeringfield for estimating risk of crashes at particular locationsBackground Project Description Guidebook Overview Conclusions Recommended Method Identify Risk.
Factors by Developing SafetyPerformance Functions Identify treatable risk factors from the model Example treatable risk factors identified from models predictingsegment related pedestrian crash types .
Presence of one or more midblock crosswalks Number of through lanes 4 or 5 Presence of a two way left turn lane TWLTL Presence of striped on street parking Presence of a right turn lane at an adjacent intersection.
Speed limits 30 mphBackground Project Description Guidebook Overview Conclusions Alternate Method Identify Risk Factorsfrom Prior Research High volumes of vehicles.
Long distance wide roads that pedestrians are exposedto on coming traffic Multiple lanes Lack of separation in space and or time Higher speed traffic.
Dark or sparsely lit roads or crossings Commercial driveways Transit activity Commercial land usesBackground Project Description Guidebook Overview Conclusions.
Alternate Method Infer Risk Factorsfrom Roadway and Crash DataBackground Project Description Guidebook Overview Conclusions Step 4 Identify Potential Treatment Combinations of identified risk factors can be used to identify prioritize sites.
Pedestrian Crossing at Non Intersection Location Struck by Through Motor Vehicle from 23 651 OriginalCombination of Roadway Number of Traffic Volume Pedestrian Volume SPF PredictedFactors Relevant Sites Range AADT Range AADP RankPresence of 4 5 thru lanes and1 425 1 060 93 600 300 7 040 1 6 585.
non zero AADP or ped volume Presence of 4 or more thru lanes946 1 060 25 000 300 7 040 1 6 585and 25 000 ADT4 5 Lanes and Presence of two .
279 5 170 71 900 300 4 440 7 4 145way left turn lane TWLTL 4 5 Lanes TWLTL and Parking 44 8 950 40 100 420 1 860 15 2 090Background Project Description Guidebook Overview Conclusions Options for Performing.
Network Screening Iterative screening and ranking methods SPF derived ranking metrics if available are useful for prioritizationBackground Project Description Guidebook Overview Conclusions.
Step 5 Select Countermeasures Criteria for selecting countermeasures Relation to systemic program focus or target crash types or locations Safety effectiveness Cost initial maintenance .
Feasibility of systemic implementation Countermeasure selection process Iterative process to match treatment sites i e exhibiting focus risk factors orcrash types with potential countermeasures Perform diagnosis at proposed treatment sites to confirm.
Background Project Description Guidebook Overview Conclusions Step 5 Select Countermeasures 12 recommended countermeasures provided in detail in Appendix Signalized or Unsignalized Unsignalized locations only Signalizedcrossing locations midblock or intersection Intersections only.
including midblock or signal isHigh visibility crosswalks In Roadway Yield to Pedestrian R1 Leading pedestrian6 sign intervalTraffic calming raised devices Advance Stop Yield Bars and R1 Longer pedestrian5 5a Sign phase.
Median crossing island Pedestrian Hybrid Beacon Restricted left turnReduce number of lanes roadCurb extension and parkingrestrictionLocation specific lighting.
Background Project Description Guidebook Overview Conclusionsimprovement Step 5 ExampleRisk Factors of Sites Potential Countermeasures1 Presence of Midblock.
High visibility crosswalk and potentially many othersCrosswalk 1 or more Advance Stop Yield Bars Signs Median Islandswith refuge and a treatment to increase yielding 2 AND 4 or 5 Thru Lanes 26.
potentially PHBs OR In Roadway Yield signs andpotentially othersAbove list as well as curb extension parking3 AND On Street Parking 12restrictions.
Step 6 Refine andImplement Treatment Provides guidance and supplementalresources for Considering additional community Example Prioritization Tool ActiveTrans Priority.
priorities Tool Guidebook Lagerwey et al 2015 Performing additional diagnostics Performing economic assessments and Allocating funding .
Example economic analysis toolfrom ODOT Siddique et al 2017 Background Project Description Guidebook Overview Conclusions Step 7 Evaluate Projects and.
Evaluate the program Process evaluation Implementation Barriers data needs Evaluate projects Safety evaluation Across all sites.
Crashes preferred or surrogate measures e g speed yielding conflicts Renew the process Improve data Update analyses.
The objective of this research was to develop a process for (1) conducting systemic safety analyses for pedestrians using analytical techniques to identify roadway features, behaviors, and other contextual risk factors such as land use that are associated with pedestrian crashes; (2) identifying appropriate and cost-effective systemic ...

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