Systemic Pedestrian Safety Analysis

Systemic Pedestrian Safety Analysis

NCHRP Research Report 893: Systemic Pedestrian Safety Analysis Final Presentation Materials MAY 2018 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 the system (or network) level Establishes common characteristics (risk factors) of locations where severe crashes frequently occur Emphasizes low-cost safety countermeasures to address the risk factors identified Prioritizes locations across the entire roadway network where risk

factors are present, regardless of prior crash history *From FHWAs Systemic Safety Project Selection Tool (Preston et al. 2013) Background | Project Description | Guidebook Overview | Conclusions Benefits of a Systemic Approach Improved safety with more proactive approach Dont simply chase the hot spots Informed decision-making utilizes data on key risk factors Optimized investment Cost-effective use of resources

Consistency in application Background | Project Description | Guidebook Overview | Conclusions Key Takeaway: Systemic Approach Definition 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 approaches seek not only to address locations with prior crash occurrence, but also those locations with similar roadway or environmental crash risk characteristics. Background | Project Description | Guidebook Overview | Conclusions

FHWAs Systemic Approach to Safety Identifies focus crash types and risk factors Screens the network to identify locations with relevant risks for treatment Identifies candidate countermeasures to address risks Prioritizes projects Identifies / allocates funding Evaluates safety and other impacts of systemic projects Background | Project Description | Guidebook Overview | Conclusions

Why Do We Need a Systemic Safety Process 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 augment existing 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 Objectives Develop a process (and Guidebook) that includes: 1) Analytical methods to identify roadway features, behaviors, and other contextual risk factors associated with pedestrian crashes 2) Methods to identify appropriate and cost-effective systemic pedestrian safety improvements to address the associated risk factors 3) Information to enable transportation agencies to prioritize candidate locations for selected safety improvements Background | 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 processes 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 high motivation to collect and compile the needed types of data to perform more robust analyses to determine factors associated with pedestrian crash risk and develop reliable prioritization metrics There is an extensive body of pedestrian risk research that could be mined for potential use (done in Phase II and incorporated into Guidebook) Background | Project Description | Guidebook Overview | Conclusions Phase II Key Findings Analysis of two types of segment-related (midblock) pedestrian collisions 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 for systemic 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 Report Background | Project Description | Guidebook Overview | Conclusions

Steps in the Guidebook Background | Project Description | Guidebook Overview | Conclusions Step 1: Define Study Scope Purpose is to identify a problem type that accounts for a large % of the problem Typically, only crash data is used Uses descriptive means such as crash tree 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 to make 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 spatial references 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 environment

Background | 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 analyses Background | Project Description | Guidebook Overview | Conclusions Advantages of a Modeling/SPF Approach

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 factor studies 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 engineering field) for estimating risk of crashes at particular locations

Background | Project Description | Guidebook Overview | Conclusions Recommended Method: Identify Risk Factors by Developing Safety Performance Functions Identify treatable risk factors from the model Example treatable risk factors identified from models predicting segment-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 mph Background | Project Description | Guidebook Overview | Conclusions Alternate Method: Identify Risk Factors from Prior Research High volumes of vehicles Long distance (wide roads) that pedestrians are exposed to 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 uses Background | Project Description | Guidebook Overview | Conclusions Alternate Method: Infer Risk Factors from Roadway and Crash Data Background | Project Description | Guidebook Overview | Conclusions Step 4: Identify Potential Treatment Sites

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 Original Segments Combination of Roadway Factors Number of Relevant Sites Traffic Volume Range (AADT) Pedestrian Volume Range (AADP)

SPF-Predicted Rank Presence of 4, 5+ thru lanes (and non-zero AADP or ped. volume) 1,425 1,060 - 93,600 300 - 7,040 1 - 6,585 Presence of 4 or more thru lanes

and < 25,000 ADT 946 1,060 25,000 300 - 7,040 1 - 6,585 4, 5+ Lanes and Presence of twoway, left-turn lane (TWLTL) 279 5,170 - 71,900

300 - 4,440 7 - 4,145 4, 5+ Lanes, TWLTL, and Parking 44 8,950 - 40,100 420 - 1,860 15 - 2,090

Background | Project Description | Guidebook Overview | Conclusions Options for Performing Network Screening / Ranking Iterative screening and ranking methods possible SPF-derived ranking metrics (if available) are useful for prioritization Background | 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 or crash 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 crossing locations (including midblock) High visibility crosswalks Traffic calming (raised devices) Unsignalized locations only (midblock or intersection) Signalized Intersections only (or signal is

added) In-Roadway Yield-to-Pedestrian (R1- Leading pedestrian 6) sign interval Advance Stop/Yield Bars and R1Longer pedestrian 5/5a Sign phase Pedestrian Hybrid Beacon Restricted left turn Median crossing island Reduce number of lanes / road diet Curb extension and parking restriction

Location-specific lighting Background | Project Description | Guidebook Overview | Conclusions improvement Step 5: Example Risk Factors 1) Presence of Midblock Crosswalk (1 or more) Number of Sites Potential Countermeasures 196 High visibility crosswalk and potentially many others 2) AND 4 or 5+ Thru Lanes

26 Advance Stop/Yield Bars & Signs, Median Islands with refuge; and a treatment to increase yielding potentially PHBs OR In -Roadway Yield signs; and potentially others 3) AND On-Street Parking 12 Above list, as well as curb extension/parking restriction s Step 6: Refine and

Implement Treatment Plan Provides guidance and supplemental resources for: Considering additional community priorities; Performing additional diagnostics; Performing economic assessments; and Allocating funding. Example Prioritization Tool: ActiveTrans Priority Tool Guidebook (Lagerwey et al. 2015) =

Example economic analysis tool from ODOT (Siddique et al. 2017) Background | Project Description | Guidebook Overview | Conclusions Step 7: Evaluate Projects and Process

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 New screening/ranking Background | Project Description | Guidebook Overview | Conclusions Examples with Key Takeaways

1. 2. 3. 4. Seattle DOT Oregon DOT Arizona DOT California DOT (Caltrans) Preliminary Identification of High-Risk Segments (ADOT 2017). Background | Project Description | Guidebook Overview | Conclusions Conclusions

Limitations and Considerations Recognition that limited data is a primary obstacle to implementing a robust systemic safety analysis process Limited data on behavior-based risk factors or examples in practice Limited research or evaluation of Steps 6-7 in practice CMFs for treatments applied systemically may differ from those applied based on crash history See Final Report for more rationale, caveats, and considerations Background | Project Description | Guidebook Overview | Conclusions Interagency Collaboration Opportunities Continued work to improve data: coverage, quality,

standardization, timeliness, and spatial linkage Pedestrian and motor vehicle traffic counts & volume estimation Build training/skills, tools, methodologies for developing SPFs for different contexts Conduct systemic countermeasure evaluations Background | Project Description | Guidebook Overview | Conclusions Future Research Needs Research/guidance on how to better measure and account for individual- or behavior-based risk factors, such as motorist speed or pedestrian behaviors Further evaluation of the safety impacts of treatments in systemic applications

Pooled sources of data or research to help quantify risk factors that are more generally applicable to many jurisdictions Studies evaluating the safety impacts of systemic vs. traditional (e.g., hotspot) approaches Background | Project Description | Guidebook Overview | Conclusions NCHRP 17-73 Contacts Project Team: Laura Sandt, Libby Thomas, Charlie Zegeer, Wesley Kumfer, Katy Lang, Bo Lan, Krista Nordback HIGHWAY SAFETY RESEARCH CENTER, UNIVERSITY OF NORTH CAROLINA CHAPEL HILL, CHAPEL HILL, NC Casey Bergh, Andrew Butsick, Zachary Horowitz, Bastian Schroeder, Joseph Toole KITTELSON & ASSOCIATES, INC., PORTLAND, OR Robert J. Schneider UNIVERSITY OF WISCONSIN-MILWAUKEE, CONSULTANT

NCHRP Program Officers: Lori Sundstrom and Ann Hartell Background | Project Description | Guidebook Overview | Conclusions NCHRP Research Report 893 For more information see NCHRP Research Report 893: Systemic Pedestrian Safety Analysis (NCHRP Project 17-73) http ://www.trb.org/Main/Blurbs/178087.aspx

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