New York State Department of Transportation Work with Local Agencies to Reduce Duplicate Data Collection and Improve Data Analysis

Background

This case study highlights two noteworthy practices at the New York State Department of Transportation (NYSDOT) regarding traffic data collection agreements with local agencies and random sampling procedures to select short-duration traffic count locations. Through agreements with local agencies, NYSDOT provides traffic counting equipment and training in exchange for short-duration traffic counts. The agreement stipulates the minimum number of counts local agencies must conduct each year, a number equal to the breakeven point between the cost of the counters and cost of conducting short-duration traffic counts. The benefits of these agreements include reducing duplicate traffic data collection efforts and costs for NYSDOT while providing additional data and analysis to partnering local agencies. NYSDOT conducted a one-time project to collect short-duration counts on a random sample of local roads not typically counted as part of the traffic data collection program. This project supplements existing count data so that at least 10 percent of the local road mileage in each municipality has short-duration counts to support local road annual average daily traffic (AADT) data collection. Random sampling provides an unbiased method to select segments for short-duration traffic counts to increase the amount of measured AADT on local roads.

Read the Case Study New York State Department of Transportation: Engagement of Local Agencies in Traffic Volume Collection and Random Sampling Procedures for more detailed information.

Virginia Department of Transportation Uses Innovative Procedures in Traffic Volume Estimation

Background

This case study presents how the Virginia Department of Transportation (VDOT) estimates traffic volumes on secondary local roadways using a trip generation method instead of taking short-duration counts in the field. The use of trip generation estimates was an outcome of a review process that aimed to reduce data collection costs and achieve manpower savings by establishing a local secondary count program. As part of this program, VDOT provided guidelines to its staff on how to identify eligible traffic links and generate traffic volume estimates using the trip generation method. According to this program, region and district staff are responsible for reviewing candidate segments using aerial photos, determining potential development and roadway connectivity, evaluating roadway eligibility criteria, documenting the trip generation process used, developing estimates, and submitting the estimates to the Central Office-Traffic Engineering Division. After implementing the method, VDOT realized several benefits, most of which are associated with time and cost savings. Because of the positive experience and feedback received with this effort, VDOT will continue to promote and improve the use of the trip generation method.

Read the Case Study Virginia Department of Transportation: Innovative Procedures in Traffic Volume Estimation for more detailed information.

Delaware Valley Regional Planning Commission’s Innovative Traffic Data Sharing Practices

This case study highlights how the Delaware Valley Regional Planning Commission (DVRPC) promotes traffic data sharing with other agencies and makes traffic and geographic information system data available to the public. DVRPC has developed an interactive mapping application, called Traffic Count Viewer that provides open access to different types of short-duration traffic counts that DVRPC and other external entities take. Traffic Count Viewer communicates with a regional database that DVRPC maintains, allowing users to view, filter, and download traffic data. Further, users can directly connect to DVRPC’s ArcGIS server map service and extract data for traffic and safety analysis. After implementing this tool, DVRPC minimized duplicate data collection efforts, increased the efficiency of its data collection program, and improved its relationships with external entities by offering no-cost access to a comprehensive data source. The Viewer also resulted in time and cost savings for DVRPC’s data partners and provided quick and easy access to data that otherwise would be difficult to obtain. DVRPC will continue to improve Traffic Count Viewer, considering its increased popularity with and positive feedback from users.

Read the Case Study Delaware Valley Regional Planning Commission’s Innovative Traffic Data Sharing Practices for more detailed information.

Illinois Develops Safety Performance Functions for Network Screening

Summary from: Roadway Safety Data Program | Development of Safety Performance Functions for Network Screening in Illinois

Background

In 2006, the Illinois Center for Transportation, Illinois Department of Transportation (IDOT), and the University of Illinois at Urbana-Champaign performed a research project to develop state-specific SPFs to use in the State’s network screening process. Prior to 2006, IDOT used the High Accident Location Identification System (HALIS) to identify High Accident Locations (HAL) and wet pavement cluster/segments that were based on crash frequency, rate, and equivalent property only. This project addressed the following specific challenges:

• linking crash and roadway data, given each had a different linear referencing system;
• establishing the criteria to assign each roadway segment to a peer group;
• using “reference points” to establish intersection locations;
• currency of crash and traffic data;
• processing a large volume of crash and roadway data; and
• helping users understand the meaning of the results.

Read the Case Study Development of Safety Performance Functions for Network Screening in Illinois for more detailed information.

Utah Collects and Uses Roadway Asset Data

Summary from: Roadway Safety Data Program | Collection and Use of Roadway Asset Data In Utah | FHWA-SA-14-078

Background

Quality data are the foundation for making important decisions regarding the design, operation, and safety of roadways. While crash data have been a consistent element of highway safety analysis, in recent years there has been an increased focus on the combination of crash, roadway, and traffic data to make more precise and prioritized safety decisions. The application of advanced highway safety analysis processes and tools requires a comprehensive inventory of roadway safety data combined with crash data to better identify and understand problems, prioritize locations for treatment, apply appropriate countermeasures, and evaluate the effectiveness of the those countermeasures. Comprehensive roadway safety data include information on roadway and roadside features, traffic operations, traffic volumes, and crashes.

Read the Case Study Collection and Use of Roadway Asset Data In Utah for more detailed information.

Virginia Develops and Uses State-Specific Performance Functions (SPFS)

Summary from: Roadway Safety Data Program | Developing and Using State-Specific Safety Performance Functions (SPFS) In Virginia | FHWA-SA-14-078

Background

The Virginia Department of Transportation (VDOT) emphasizes data-driven decision-making and desires to improve safety and safety data. From this desire, VDOT implemented a comprehensive set of State-specific Safety Performance Functions (SPFs) covering 98 percent of its State-maintained roadway locations. The impetus for VDOT developing their own SPFs and analytical tools arose from the decision that AASHTOWare Safety Analyst™ did not meet their needs. VDOT developed State-specific SPFs using historical crash, traffic, and roadway inventory data. SPF developers worked closely with engineers throughout the development process to see whether each SPF was implementable for all types of improvements (spot, corridor, and systemic). To date, VDOT has developed 24 SPFs covering a majority of roadway facilities, including two-lane roads, intersections, and freeways/multi-lane highways.

After performing network screening, the VDOT central office identifies the top 100 sections and top 100 miles of segments with the largest Potential for Safety Improvement (PSI). The list is then sent to the district engineers who determine which sites to prioritize based on practical experience and knowledge of their area. VDOT has noted several benefits of Virginia’s SPF implementation effort. For example, the advanced data-driven process leads to better use of funds, benefits for both systemic and spot improvements are quantifiable, VDOT can better manage public concerns, and VDOT can compare locations to prioritize projects. The SPF development team conducts training (including an annual “roadshow” to all nine districts) and hosts webinars to ensure district engineers understand the methodology and how to use the SPFs. VDOT has not mandated the use of SPFs and PSIs by the districts because the process of introducing a new methodology takes time, but the district engineers know it is the preferred method for network screening.

Read the Case Study Developing and Using State-Specific Safety Performance Functions (SPFS) In Virginia for more detailed information.

Utah Department of Transportation Uses Safety Data Processes and Governance Practices

Summary from: Roadway Safety Data Program | Utah Department of Transportation Safety Data Processes and Governance Practices | FHWA-SA-15-060

Background

The purpose of this case study is to highlight innovative data management strategies at Utah Department of Transportation (UDOT) that support the use of technology to benefit safety programs. In addition to highlighting forward-thinking strategies for safety data management, data analysis, and reporting, the case study documents the need for a formal data business plan and data governance. Exploring data management practices and the use of innovative tools within UDOT provides safety data management examples of:

• The importance and usefulness of a robust and well-managed data collection program.
• Providing access to integrated data for a variety of purposes.
• How to use integrated data to develop advanced safety analysis capabilities and at the same time support tools for planning, performance measures, and target-setting processes.
• The importance of collaboration and sharing current data strategies and challenges with data stakeholders.

Read the Case Study Utah Department of Transportation Safety Data Processes and Governance Practices for more detailed information.

New Hampshire Department of Transportation Uses Safety Data Systems and Processes to Improve Traffic Safety

Summary from: Roadway Safety Data Program | New Hampshire Department of Transportation Safety Data Systems and Processes | FHWA-SA-15-058

Background

The purpose of this case study is to highlight noteworthy practices of the New Hampshire Department of Transportation (NHDOT) in leveraging technology to enhance safety data management—in particular, NHDOT’s use of an integrated Linear Referencing System (LRS) and use of information technology (IT) tools to analyze safety data (e.g., AASHTOWare Safety Analyst™, American Association of State and Highway Officials (AASHTO) Highway Safety Manual (HSM), and Graphical Information Systems (GIS) tools). New Hampshire’s use of technology improves management of safety data systems by providing mechanisms for:

• Electronic data collection, thereby reducing data errors at the point of collection;
• Integration of data from different systems, using GIS and a consolidated LRS;
• Access to multiple types of safety data through a single portal that extracts and displays crash, traffic, and road inventory data; and
• Analysis of data for identification of high crash “hot spots,” or locations with potential for safety improvement, using safety performance functions to estimate expected crash frequency of all sites across the road network.

Read the Case Study New Hampshire Department of Transportation Safety Data Systems and Processes for more detailed information.

Michigan Department of Transportation Uses Safety Data Processes

Summary from: Roadway Safety Data Program | Michigan Department of Transportation Safety Data Processes and Governance Practices | FHWA-SA-15-059

Background

The purpose of this case study is to summarize how the Michigan Department of Transportation (MDOT) incorporates a data governance structure into their standard business operations and how it has helped them to improve their safety data systems and processes. “Data governance can be defined as the execution and enforcement of authority over the management of data assets and the performance of data functions” (NCHRP Report 666, 2010) and is an integral component used to facilitate management of data systems as part of an agency’s data business plan.

In the case of MDOT, a set of data governance practices provides the foundation needed to develop a comprehensive Data Business Plan, to support MDOT’s Strategic Highway Safety Plan Highway Safety Improvement Program, and improve information systems that manage data needed for safety analysis, planning, and decision-making.

Read the Case Study Michigan Department of Transportation Safety Data Processes and Governance Practices for more detailed information.

New Hampshire Develops Intersection Inventory to Improve Road Safety

Summary from: Roadway Safety Data Program | New Hampshire’s Intersection Inventory | FHWA-SA-15-087

Background

One of the major challenges transportation agencies face when trying to address intersection safety is not having a sufficient intersection inventory that provides location, operations, or geometrics of the intersections. In 2010, the Federal Highway Administration (FHWA) released the Model Inventory of Roadway Elements (MIRE), which is a recommended list of roadway and traffic volume data elements important to safety management and analysis. The New Hampshire Department of Transportation (NHDOT) was one of two States selected by FHWA to participate as a Lead Agency in the MIRE Management Information System (MIS) effort. FHWA conducted the MIRE MIS Lead Agency Program pilot project to test the feasibility of collecting, storing, and integrating MIRE data into an MIS and then linking roadway inventory data with crash and other relevant data for safety analyses.

NHDOT chose to focus their data collection effort on the acquisition of additional intersection elements to expand its use of AASHTOWare Safety Analyst™ primarily to support network screening analyses. After NHDOT completed data collection and integrated the data into the system, they now use the inventory for evaluating roadway safety countermeasures and for performing economic analysis. The intersection inventory supports better safety analysis using data specific to New Hampshire’s roadway network instead of default values or national averages. New Hampshire has benefitted from the state-specific data by targeting their spending by comparing sites and prioritizing locations with greater potential for improvement.

Read the Case Study New Hampshire’s Intersection Inventory for more detailed information.