Work Zone Mobility and Safety Program
Work zone management program

The National Performance Management Research Data Set and Work Zone Mobility Performance Measurement

Performance measures enable agencies to monitor their transportation system and identify improvements or mitigation strategies as needed. They serve as indicators for the effects of any changes to the transportation system, such as the introduction of a work zone. Key work zone mobility performance measures include travel time, speed, delay, queues, throughput, travel time reliability, and road user costs.3

Traditionally, transportation agencies have struggled to accurately measure and monitor the mobility performance of their work zones due to a lack of data —both mobility data and accurate work zone activity data. One solution to a lack of mobility data is the NPMRDS, which provides mobility data collected anonymously from a fleet of probe vehicles (i.e., cars and trucks) equipped with mobile devices. Using time and location information from probe vehicles, the NPMRDS generates speed and travel time data aggregated in 5-minute, 15-minute, or 1-hour increments. The variable data granularity offered by the NPRMDS allows users to customize their analyses according to their desired level of granularity. The data are available across the National Highway System (NHS), with a spatial resolution defined by Traffic Message Channel (TMC) location codes. A TMC represents a unique, directional roadway segment that is about half a mile to a mile long in urban and suburban areas and could be as long as five to ten miles long in rural areas. The NPMRDS covers more than 400,000 TMCs and includes several billions of speed and travel time observations across the NHS for both freeways and arterials. The NPMRDS has been available since 2013, with freeway data dating back as far as 2008. Please refer to the accompanying NPMRDS fact sheet for details on using NPMRDS data for work zone performance management.4

An example of how State DOTs can use NPMRDS data to systematically measure work zone mobility performance using a 10-step process is shown in figure 1. The process draws upon existing FHWA resources on transportation and work zone performance measurement but is specifically customized to using the NPMRDS as the data source. NPMRDS travel time and speed data are the foundational mobility metrics for this process. Using these foundational metrics as a basis, State DOTs can calculate a variety of performance metrics (e.g., work zone travel time, speed, delay, travel time variability, and road-user costs). The process provides for a systematic, repeatable, inexpensive, and easy-to-adopt process for work zone performance measurement. A detailed discussion of the 10 steps is provided in the Appendix.

The 10 steps of the example process are listed: 1. Gather Construction Information, 2. Determine Analysis Type, 3. Select Performance Metrics, 4. Download NPMRDS Data, 5. Establish Performance Thresholds, 6. Perform Calculations, 7. Interpret Results, 8. Take Intervention / Project Actions, 9. Develop Report, 10. Document Lessons Learned for Planning Purposes

Figure 1. Chart. Example process for estimating work zone mobility impacts using the National Performance Management Research Data Set
Source: FHWA

Agencies can use NPMRDS data to systematically analyze work zone mobility performance, take appropriate remedial actions, and better manage the mobility performance of their work zones5, including:

Managing and Monitoring the Performance of Individual Projects

  • Developing a baseline of system performance prior to implementation of the work zone
  • Estimating work zone mobility impacts during planning and design
  • Conducting ongoing6 and post-hoc work zone mobility performance measurement and management

    • Corridor-, District-, and/or Agency-Level Work Zone Reporting and Management

    • Aggregating work zone performance at the corridor, network, region/district, and agency-wide levels
    • Comparing and trending across different projects, project types, and work zone activity types
    • Incorporating work zone performance measures into annual mobility reports and broader Transportation System Management & Operations (TSMO) efforts
    • Incorporating work zone performance measures into the Congestion Management Process as part of a cause of congestion (non-recurrent)

    Incorporating Work Zone Performance Measures into Bi-Annual Work Zone Performance Reviews

    • Using quantitative NPMRDS measures to supplement and substantiate qualitative process review findings
    • Correlating measured performance against agency actions and improvements
    • Comparing performance across years, identifying cause and effect, and taking improvement actions

    3 As the phrase is used in this document, “performance measures” do not refer to those performance measures required under FHWA regulations. Rather, “performance measures” refer to mobility performance measures that are widely accepted and used by State and local practitioners and industry.

    4 The National Performance Management Research Data Set (NPMRDS) and Application for Work Zone Performance Measurement, FHWA-HOP-20-029, https://ops.fhwa.dot.gov/wz/decision_support/perf_meas_examples.htm

    5 The work zone safety and mobility provisions under 23 CFR 630 Subpart J (https://www.ecfr.gov/current/title-23/chapter-I/subchapter-G/part-630/subpart-J) require States to continually pursue improvement of work zone safety and mobility by analyzing work zone crash and operational data from multiple projects to improve work zone processes and procedures.

    6 Applicable to projects that last longer than a month. NPMRDS data are updated monthly; the prior month’s data are usually available by the fifth of every month.

    < Previous | Table of Contents | Next >

    Office of Operations