Iowa Uses Real-Time Data Integration of Snowplow Information and Roadway Safety

Summary from: Roadway Safety Data Program | Iowa’s Real-Time Data Integration of Snowplow Information and Roadway Safety | FHWA-SA-16-030

Background

The Iowa Department of Transportation (DOT) deploys about 900 snowplows each winter to plow 9,479 centerline miles of road and 25,215 lane miles of roadway. The Iowa DOT continuously seeks ways to improve winter operations and provide information to the traveling public. A current effort involves the Iowa DOT deploying the Plow Cam Project—a statewide real-time integration system. The project, started in winter 2013-2014, involves collecting up-to-date photos that create a database of road conditions.

To gather this information, the Iowa DOT used its existing communications infrastructure and the snowplows deployed on a regular basis in the winter. The process also required an iPhone (with camera and GPS), an Iowa DOT-developed app, phone charger, cigarette lighter socket and fuse, and a suction cup phone mount. The iPhone is mounted inside the front windshield of the snowplow; once activated, it automatically takes photos and accumulates data.

The information collected from the snowplow cameras is available for internal and public use. The public accesses the information through its Track A Plow web site, which provides snowplow locations, as well as up-to-date Plow Cam photos.

Read the Case Study Iowa’s Real-Time Data Integration of Snowplow Information and Roadway Safety for more detailed information.

Colorado Uses GIS to Implement Level of Service of Safety

Summary from: Roadway Safety Data Program | Colorado’s Implementation of Level of Service of Safety: Strategies For Using GIS to Advance Highway Safety | FHWA-SA-16-027

Background

Design engineers at the Colorado Department of Transportation (CDOT) developed the LOSS method as an alternative to using crash rates for evaluating safety. The LOSS method compares a roadway segment’s observed crash frequency and severity to the crash frequencies and severities predicted by Safety Performance Functions (SPFs). Relying on crash rates alone to identify safety deficiencies is problematic because crash rates imply a linear relationship between exposure and safety. However, the number of crashes fluctuates based on traffic volume.

Transportation agencies that model crash frequency and severity based on annual average daily traffic (AADT) develop SPFs for public roadways, including segments and intersections. They stratify SPFs by the number of lanes, number of legs, traffic control, terrain, environment, and functional classification. Once transportation engineers and planners develop the SPFs, they can employ the LOSS method. While it is possible to segment roadway data in tabular form, using a Geographic Information System (GIS) greatly facilitates segmentation of these roadways. More specifically, GIS enables analysts to spatially link data describing roadway geometry with crash data. For intersections, it is necessary for analysts to use some special context to link intersecting roadways, as a tabular dataset cannot use GIS to link intersecting roads.

Read the Case Study Colorado’s Implementation of Level of Service of Safety: Strategies For Using GIS to Advance Highway Safety for more detailed information.

Tennessee Develops Horizontal Curve Database

Summary from: Roadway Safety Data Program | Tennessee’s Horizontal Curve Database | FHWA-SA-16-048

Background

In 2012, The Tennessee Department of Transportation (TDOT) accomplished its initial data collection for its entire roadway network, which includes all interstates, state highways, arterials, collectors, and local roads. With these data, TDOT created a horizontal curve database with approximately 40,000 miles of roadways with curves, which is housed in the Tennessee Roadway Information Management System (TRIMS)—a client-server application that allows TDOT to capture, maintain, and view critical roadway data. TDOT uses the horizontal curve database to provide quick, data-derived answers to public concerns, make data-driven decisions, quantify potential benefits from both systemic and spot improvements, and compare curves with similar characteristics to help prioritize projects.

Read the Case Study Tennessee’s Horizontal Curve Database for more detailed information.

Utah and Kentucky Make Innovative Use of GIS-Based Tools

Summary from: Roadway Safety Data Program | Utah’s and Kentucky’s Innovative Use of GIS-Based Tools | FHWA-SA-16-028

Background

The United States Road Assessment Program (usRAP) is a tool transportation agencies can use to rate their roadways for safety and identify strategies for systematic improvement. UPlan is an interactive mapping platform that helps the Utah DOT (UDOT) visualize its data, track its assets, and strengthen its transportation planning through “better analysis and collaborative information.” UPlan’s Zero Fatalities safety component presents UDOT’s Safety and Crash Analysis, which is predicated on the mapping and road-rating tools first developed by usRAP. usRAP and UPlan safety components both employ similar general processes and have the same objective: to increase safety by understanding and mitigating crash risks and roadside hazards.

At the core of usRAP is a focus on risk assessment to identify practical solutions to roadway safety problems. usRAP uses crash and roadway data to map relative road risk using a number of standardized protocols. A roadway network is systematically divided into segments for data analysis and presentation of results. Attributes of each segment are used to quantify fatal and serious injury crash risk. Color-coded risk maps summarize the findings.

UDOT developed UPlan as part of an AASHTO Innovation Initiative. According to AASHTO:

UPlan is a powerful, yet easy-to-use web-based decision-support mapping and informational tool for completing complex planning and project development tasks. It allows complete or selective data sharing among various work units within the state DOT. It also allows selective data sharing between state DOTs and with the public.
– AASHTO Innovation Initiative (AASHTO 2016)

UPlan is a comprehensive infrastructure-management system that relies extensively on geospatial data. DOTs can use these available data to make safety, pavement, and roadway asset management decisions. In Utah, UPlan uses data-collection methods, such as LiDAR, digital imaging, workstation, and ArcGIS records to cover 5,845 centerline miles and 310 miles of ramps and collectors on State-maintained roads. Several government entities jointly performed the data collection, and each agency can use its products.

Read the Case Study Utah’s and Kentucky’s Innovative Use of GIS-Based Tools for more detailed information.

Arizona Imports Local and Tribal Data for Safety Analysis

Summary from: Roadway Safety Data Program | Arizona Importing Local and Tribal Data for Safety Analysis | FHWA-SA-16-061

Background

The Arizona Department of Transportation (ADOT) and the Federal Highway Administration (FHWA) Office of Safety completed a pilot project that allows the State to acquire roadway data elements from local and Tribal agencies and load the data into the Arizona Transportation Information System (ATIS) database. ADOT created a new process that allowed business users to import the data from local agencies, export combined State and local/tribal data, and load data into AASHTOWare Safety Analyst™ for analysis. ADOT used contractor support to establish data integration procedures for crash, roadway, and traffic volume data for both roadway segments and intersections. The results from the pilot created processes for the data submissions to ADOT, data integration in ATIS, the process for bringing data into AASHTOWare Safety Analyst™, and quality control checks prior to analysis.

Read the Case Study Arizona Importing Local and Tribal Data for Safety Analysis for more detailed information.

North Carolina Creates State-Specific CMFs

Summary from: Roadway Safety Data Program | North Carolina’s State-Specific CMFs | FHWA-SA-16-107

Background

North Carolina is one of a small number of States that have actively pursued developing their own crash modification factor (CMF) “short list” for countermeasures that are deployed throughout the State. It is important that all safety units across North Carolina use the same CMF value for a particular countermeasure in their benefit-cost analyses so that each safety unit has a level playing field when competing for safety dollars.

North Carolina’s Department of Transportation (NCDOT) wanted to develop a list of CMFs to use in benefit-cost analyses across the State. To develop the CMF list, NCDOT first reviewed studies found online. Later, they reviewed the available CMFs in the CMF Clearinghouse. The primary benefit that NCDOT has realized from conducting evaluations of countermeasures that previously had subjective CMF values is that the agency does not continue to implement countermeasures that have little to no quantifiable crash benefit. This is especially helpful with project selection processes and makes better use of safety dollars.

Read the Case Study North Carolina’s State-Specific CMFs for more detailed information.

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.