Illinois Implements Enterprise Data Governance Approach for Improved Road Safety

Summary from: Roadway Safety Data Program | Roadway Safety Data Governance in Illinois | FHWA-SA-16-108

Background

The Illinois Department of Transportation (IDOT) has implemented an enterprise data governance approach for managing the collection, storage, distribution, and usage of data across the organization. IDOT has also established a spatially-enabled data warehouse to integrate crash, roadway, and traffic data. The Illinois Traffic Records Coordinating Committee (ITRCC) serves as IDOT’s formal safety data governance group, which include the Engineering Subcommittee and the Data Quality Subcommittee. The Engineering Subcommittee is developing a comprehensive safety data system to enable safety analyses, which includes identifying severe crash locations and segments, prioritizing locations for treatment, and performing systemic safety analyses. The Data Quality Subcommittee ensures availability of complete, accurate, and timely motor vehicle crash data for transportation safety decision-making. IDOT also offers safety analysis tools, provides safety data training and technical assistance, and promotes local access to crash and roadway data. Through these various data governance and management activities, IDOT integrates a wide variety of safety-related data for decision making in comprehensive transportation program development.

Read the Case Study Roadway Safety Data Governance in Illinois for more detailed information.

Illinois Conducts State-Specific Highway Safety Manual and Systemic Safety Analysis

Summary from: Roadway Safety Data Program | State-Specific Highway Safety Manual and Systemic Safety Analysis In Illinois | FHWA-SA-17-014

Background

The Illinois Department of Transportation (IDOT) published the AASHTO Highway Safety Manual Illinois User Guide with Illinois Calibration Factor and Default Values in 2014. This guidebook provides guidance on incorporating AASHTO Highway Safety Manual (HSM) methods into Illinois roadway safety management practices. IDOT calibrates Safety Performance Functions from the HSM for calculating the predicted crash frequency on specific roadway facility types and site types in Illinois. Also in 2014, IDOT published the Systemic Safety Improvements: Analysis, Guidelines and Procedures guidebook, and IDOT uses this guide to systemically analyze crash, roadway, and facility information, select countermeasures, and prioritize safety-related projects. IDOT employs a variety of tools and techniques to improve roadway safety in the State, including GIS integration, County Data Trees, Emphasis Area tables, Heat Maps, and a Five Percent Report.

Read the Case Study State-Specific Highway Safety Manual and Systemic Safety Analysis In Illinois for more detailed information.

Alabama Creates Safety Planning Tools for MPOs

Summary from: Roadway Safety Data Program | Alabama’s Safety Planning Tool for MPOs | FHWA-SA-17-015

Background

The Alabama Department of Transportation (ALDOT) led the effort to develop ALSAFE, a spreadsheet-based safety tool that can be used for short- and long-range transportation safety planning. ALDOT developed ALSAFE to serve as a safety planning tool for Metropolitan Planning Organizations (MPOs). The short-range planning process allows MPOs to develop benchmarks and performance measures, evaluate crash trends and patterns, and identify potential countermeasures for further evaluation. The long-range planning component of ALSAFE provides predictive equations to estimate changes in crash frequency or severity influenced by area-wide planning characteristics. ALDOT is currently conducting Phase II of the ALSAFE project, where ALDOT will replicate the ALSAFE tool and process for three more MPOs.

Read the Case Study Alabama’s Safety Planning Tool for MPOs for more detailed information.

Maryland Supports Decision Making with Data Linkage and Analysis

Summary from: Roadway Safety Data Program | Maryland’s Data Linkage And Analysis To Support Decision Making | FHWA-SA-16-049

Background

Highway traffic safety analysis is a multi-dimensional process involving roadway characteristics, volumes, and crash data. State agencies may encounter difficulties sharing data between agencies and integrating the multiple data sources into a single safety analysis. The University of Maryland’s National Study Center for Trauma and Emergency Medical Services (NSC) receives data from several State agencies and provides integrated data analysis using the Crash Outcome Data Evaluation System (CODES) methodology. CODES helps States develop data linkage programs as crash data alone do not capture the full consequences of motor vehicle crashes. The intent of the CODES program was to provide a more comprehensive understanding of motor vehicle crashes by linking crash, vehicle, and behavior characteristics to their specific medical and financial outcomes. The purpose of this case study is to describe some of the unique qualities and successes of the Maryland CODES program and to explore how the NSC uses advanced CODES integration and safety analysis to support a variety of agencies and programs.

Read the Case Study Maryland’s Data Linkage And Analysis To Support Decision Making for more detailed information.

South Carolina Uses Electronic Crash System Deployment for Safety Data Improvements

Summary from: Roadway Safety Data Program | South Carolina Safety Data Improvements Through Electronic Crash System Deployment | FHWA-SA-16-109

Background

The South Carolina Department of Transportation (SCDOT) and the South Carolina Department of Public Safety (SCDPS) implemented the South Carolina Collision and Ticket Tracking System (SCCATTS), a long-term initiative to improve law enforcement data quality. SCCATTS supports decision making with quality data and by efficiently sharing data among stakeholders. The benefits of SCCATTS include providing a standardized way for law enforcement to process crash and citation data through a streamlined electronic process, obtaining more timely, accurate, and complete crash and citation data, data-driven decision-making, and delivering data to stakeholder agencies electronically, eliminating the paper-based process.

Read the Case Study South Carolina Safety Data Improvements Through Electronic Crash System Deployment for more detailed information.

Pennsylvania Develops State-Specific SPFs and CMFs

Summary from: Roadway Safety Data Program | Pennsylvania’s State-Specific SPFs and CMFs | FHWA-SA-16-062

Background

The Pennsylvania Department of Transportation (PennDOT) used Part C of the Highway Safety Manual (HSM) to develop State-specific safety performance functions (SPFs). For some facility types, PennDOT developed district/regional-level calibrations of the State-specific SPFs. PennDOT developed regional SPFs and calibrated State-specific SPFs for use at the regional level. They believe this is the best approach for dealing with the inherent differences among areas within the State.

The PennDOT Highway Safety and Traffic Operations Division developed a guide on the appropriate use of State-specific crash modification factors (CMFs). This guide is based on a critical review of the CMFs available in the FHWA CMF Clearinghouse to identify CMFs applicable to Pennsylvania. PennDOT’s “Pennsylvania CMF Guide” includes information on these selection criteria as well as best practices to guide practitioners on how to use CMFs appropriately in various scenarios. As the list of countermeasures in the CMF Clearinghouse continues to grow, practitioners can use the criteria to select from among the newly added CMFs.

Read the Case Study Pennsylvania’s State-Specific SPFs and CMFs for more detailed information.

Washington State and Tribes Share Data to Improve Transportation Safety

Summary from: Roadway Safety Data Program | Washington State and Tribal Data Sharing Partnerships | FHWA-SA-16-111

Background

In Washington State, the traffic fatality rate for Native Americans is 3.5 times higher than the rest of the population. Tribal and State agencies have recognized the need for improved data in order to accurately identify and address Tribal transportation safety challenges. In 2007, the Washington State developed the eTRIP/SECTOR software program to efficiently bring together data sources and share data. While some Tribes have begun using the software, other Tribes have expressed data security concerns. Washington Traffic Safety Commission has been working as liaison between Tribal agencies and the eTRIP/SECTOR team to address those concerns and facilitate Tribal transportation data sharing.

Read the Case Study Washington State and Tribal Data Sharing Partnerships for more detailed information.

Oregon Consolidates Transportation Data

Summary from: Roadway Safety Data Program | Asset Management in Oregon | FHWA-SA-16-110

Background

With almost 20,000 lane miles on the Oregon highway system, the Oregon Department of Transportation (ODOT) is responsible for managing and maintaining its roadway assets. Managed assets include barriers, traffic signals, lighting, pavement markings, and signs. ODOT has developed an inventory of its assets and evaluates asset condition in order to efficiently manage maintenance efforts. Over several years, ODOT implemented two new programs to manage their roadway assets, TransInfo and the Features, Attributes, and Conditions—Statewide Transportation Improvement Program (FACS-STIP) Tool. TransInfo is a statewide asset management system. It provides ODOT asset management staff with the most up-to-date statistics on assets and other features on the State highway system. The FACS-STIP Tool is a web-based program that provides information on an asset’s location, attributes, and condition to all users with internet access.

Read the Case Study Asset Management in Oregon for more detailed information.

HSIP Program Evaluation and Progress Reporting in New York

Problem/Issue

The New York State Department of Transportation (NYSDOT) is a decentralized organization comprised of 11 regions. As part of the Highway Safety Improvement Program (HSIP), the central office sends out a list of Priority Investigative Locations (PILs) and High Accident Locations (HALs) to the regions each spring. The regions use this information to create their Annual Regional Work Program. Specifically, the regions conduct approximately 350 Highway Safety Investigations (HSIs) annually to evaluate 20 percent of the high crash locations. The HSIs result in capital projects, which are often low-cost safety improvements, but can include more costly reconstruction projects at locations with correctable crash patterns.

While the regions are responsible for implementing safety projects, the central office is primarily responsible for conducting evaluations and tracking statewide statistics and progress as part of the Highway Safety Improvement Program (HSIP). The central office developed an annual HSIP report and statewide progress report, but these were the only feedback mechanisms for both the State and the regions. The central office wanted a way to track overall progress toward the regional work plans and several other organizational goals: HSI completion, percent obligation of HSIP funds, and implementation of focused safety programs (e.g., installation rates of centerline rumble strips and pedestrian countdown timers). When the central office gathered regional representatives to present a statewide progress report, the regions requested more nuanced reports to show progress at the regional level.

Prior to developing regional reports, it was important to the central office to stress that reporting at the regional level was not intended to highlight individual regions for lagging behind or not meeting goals. Rather, the intent was to improve performance management and encourage regions through positive feedback. If a region was lagging behind, then the central office worked with the region to identify and resolve the challenges or issues.

Solution

As a result, NYSDOT now implements an activity-based approach to program evaluation and progress reporting. The central office develops quarterly reports that contain a number of performance measures—both automated and manual components—including the number of activities performed by each region. Then, the central office gathers the regional traffic engineers to present and review the progress reports.

The report is a management tool that aims to provide a summary of the State’s progress as a whole, track work plan progress, and bring any regional resource or process issues to light for discussion. As the regions identify issues, they can work together with the central office to develop solutions. To allay some of the concerns that the reports would negatively highlight some regions over others, the central office only distributes the quarterly reports internally and only distributes the regional dashboards to the individual region. Executive management and regional traffic engineers receive the reports, which emphasize areas in need of improvement and areas of excellence. Additionally, NYSDOT provides one-page dashboards summarizing fatalities, serious injuries, and progress toward SHSP emphasis area performance measures.

Benefits

NYSDOT uses the quarterly reports to continually track and evaluate HSIP projects and programs. For example, the central office tracks the number of times a site appears on the HSI list, which allows them to assess how well the system is working. The documentation of HSIs and follow-up evaluations of resulting projects helps to defend against tort claims. Regional traffic engineers are also positioned to track and evaluate projects in their regions. This improves their knowledge of the greatest needs and challenges as well as the most successful projects. Together, the central and regional offices have a better understanding of how activities and projects contribute to the statewide safety goals and outcomes.

One region in particular was falling behind due to resource management issues. When their progress was revealed in the quarterly report, the region worked with the central office to modify its processes and allocate resources more effectively, resulting in a dramatic improvement that was reflected in subsequent progress reports.

Although the detailed reports were initially requested by the regions, the data they provide has helped achieve both regional and central office goals. Now, the central office better understands the importance of messaging and project rollout, which have become important for progress reporting. In turn, the ongoing communication from the central office has led to improved project tracking and ownership at the regional level.

The reporting practice has also created opportunities for additional improvements across the system. For example, the central office identified the opportunity to enhance HSIP evaluation practices by reducing the number of HSIs required.

Contact

Regina Doyle
New York State Department of Transportation
(518) 485-0164
Regina.Doyle@dot.ny.gov

HSIP Countermeasure Evaluation in Kentucky

Problem/Issue

The Kentucky Transportation Cabinet (KYTC) is responsible for performing Highway Safety Improvement Program (HSIP) evaluation, including project tracking and crash modification factor (CMF) development. While KYTC staff administer and provide high-level guidance on the HSIP, they have limited in-house capacity and capability to develop CMFs and delve deeper into specific statistical issues. One statistical issue is related to sample size, where there are small sample sizes of a particular treatment due to high construction costs or unique situations in which it is implemented. KYTC has been challenged with finding statistical analysis strategies to best evaluate the benefits of countermeasures with small samples.

Solution

To address these issues, KYTC turned to their long-standing partnership with the Kentucky Transportation Center (KTC), housed within the University of Kentucky. The Division of Traffic Operations in KYTC’s Central Office administers Kentucky’s HSIP funds. Using these funds, KYTC sets up a contract with KTC to provide technical assistance such as data analysis, evaluation of project effectiveness, evaluation of project completion, HSIP Annual Report assistance, and other technical activities that support HSIP administration in Kentucky. The agreement typically runs for two-year periods, functioning much like an on-call agreement. The relationship between the two organizations works efficiently and has allowed Kentucky to perform HSIP evaluations and experiment with unconventional evaluation methods to address concerns with small sample sizes.

Benefits

The strong relationship between the agencies demonstrated its value when KYTC initiated a study to evaluate the safety effects of three focused safety programs: rumble strips, high friction surface treatments, and cable median barriers. Historically, KYTC and KTC have used the Empirical Bayes (EB) before-after approach for HSIP evaluations to estimate the expected change in crash frequency. In these evaluations, KTC identified small sample sizes as a potential challenge to using the EB approach. In addition to the EB method, KTC suggested the Wilcoxon signed-rank test of proportions¹ to compare the safety performance before and after implementation.

Countermeasures such as rumble strips, high friction surface treatments, and cable median barriers target specific crash types such as run-off-road and head-on crashes. While the EB method would indicate the expected change in crash frequency for a given crash type, the Wilcoxon signed-rank test would indicate if the proportion of target crash types changed after implementation. Specifically, the Wilcoxon signed-rank test of proportions assesses the statistical significance of before-after shifts in target crashes proportionately. In this process, using the proportion of target to total crashes, the target crash types are normalized by total crashes at each site for before and after periods.

KTC used both the EB before-after method and the Wilcoxon signed-rank test to evaluate the safety effects of the three programs. The EB before-after method served as a comparison to the results from the Wilcoxon signed-rank test. A comparison of the results demonstrated a general consistency in results between the Wilcoxon signed-rank test and the EB method, recognizing the Wilcoxon signed-rank test focuses on crash proportions and the EB method focuses on mean crash frequencies. While statistical methods are not a replacement for a large sample of high-quality data, these results suggested the Wilcoxon test can be used as further verification when evaluating countermeasures. The literature suggests the Wilcoxon signed-rank test can support statistical analysis with relatively small sample sizes, particularly when there is a large shift in proportions from the before to the after period and the shift is relatively consistent across sites.² The required sample size increases as the shift in proportions decreases and as the variance of the shift in proportions increases among sites.

KYTC and KTC will continue to use the Wilcoxon signed-rank test as a complementary method to the EB analysis. The two agencies will also continue to work together to explore new methods for project evaluation and build from past experience. For example, as part of the cable median barrier evaluation, KYTC identified an issue with how police officers are coding median crossovers on crash reports. In response, KTC performed a manual review of hundreds of police reports and created an algorithm to determine whether a median crossover actually occurred in a crash. There are follow-up efforts to educate officers on the appropriate criteria for reporting median crossovers.

Contact

Tracy Lovell
Division of Traffic Operations, Kentucky Transportation Cabinet
(502) 782-5534
Tracy.Lovell@ky.gov