Welcome to the Documentation section of the National Performance Research Data Set (NPMRDS) Platform. This platform was started as a means to process and visualize the NPMRDS data for New York State Department of Transportation (NYSDOT) and the New York Association of Metropolitan Planning Organizations (NYSAMPO). The software modules contained within are useful in understanding congestion and reliability, and include auxiliary modules for analysis of traffic counts and incidents (i.e., accidents, construction). There are a number of different modules to discuss throughout this documentation as well as measures to define. Each module and data measure will have a section within the documentation:
The Macro Tool is a great tool to start your analysis. It is best for ranking the Traffic Messaging Channel (TMC) segments in your region. It provides an easy export option for looking at the entire collection of segments in your region, and for exporting a variety of different measures for each segment. The Macro Tool can be used to rank bottlenecks and to download performance measure data to begin calculating the costs of delay.
The Route Reports Tools are a data analysis Business Intelligence (BI) tool that allows users to make smaller collections of segments, such as corridors, intersections, or areas, for deeper, detailed analyses. A user can create their own routes and save them to their collection before opening a blank Report tool to build a completely custom report, or open a template for a quick start report. Templates cover a wide variety of use-cases from year over year comparisons, to before-after analyses, seasonality, monthly or day-of-week analyses, and many, many more. The templates on the landing page are designed to answer common transportation planning questions.
The PM3 measures are the highest aggregation of the data providing a cursory overview of regional and county network performance.
As an analyst, the NPMRDS tools can provide you with a wealth of relevant information. A basic workflow will help you determine how to approach the tools and get the most from them. First, a problem or need is identified. In order to address this problem or need, the case study would determine which questions need to be asked. One or more analyses are constructed to provide answers to the questions. This can be broken down into three steps:
Analysts can use the NPMRDS identify recurrent congestion locations, ranking bottlenecks, and calculating cost of delay. Each transportation planning question or need that can be addressed by the NPMRDS Tool has been considered and organized into easy to use templates and maps where default settings have been selected and minimal effort is required by the analyst to arrive at answers. Frequently asked transportation planning questions and common transportation planning needs can be found in the Quick Start Guide. The landing page Regional Analyses and Focus Analyses provides a series of links to the templates and maps that satisfy most of your needs!
The NPMRDS is a probe speed data product provided by the Federal Highways Administration (FHWA) to state departments of transportation. The current provider of the data is INRIX via the CATT Lab at the University of Maryland. The data was provided by HERE from 2016-2018.
The NPMRDS is a collection of traversal times across discrete segments from probes such as consumer and fleet smartphone navigation applications and vehicle navigation systems. All probes in a 5-minute “epoch” are averaged together to a single travel time for each segment for each epoch. There are 288 5-minute epochs in a given day. Each segment has the potential for 288 data points per day, though many epochs contain null values, especially in the overnight hours or on roads with lower Annual Average Daily Traffic (AADT). Interstate highways tend to have the highest reporting averages due to the high traffic volumes of freight and passenger vehicles.
The NPMRDS network covers most of the National Highway System (NHS) including limited access highways, arterials and some other state and county roads. The data is delivered on the TMC network which is a network designed for the radio messaging technology that delivers traffic and travel information to motor vehicle drivers in specific locations. Each TMC has a unique identifier but there are no uniform lengths. Some segments are as small as under a tenth of a mile, including intersection segments, and others are as long as over ten miles, such as rural highway segments.
The data arrives as the TMC ID, the epoch number (1 being 12:00-12:05AM, and 288 being 11:55PM-12:00AM), and the traversal time in seconds. To transform that traversal time into speed requires the NPMRDS network file, which includes TMC ID and a variety of road attributes such as length. There are a variety of performance measures that are possible with the NPMRDS data including average speeds and travel times, congestion measures, reliability measures, and incident delay.
The NPMRDS is a great tool for transportation planners and engineers. It provides a detailed understanding of average travel times and speeds, that can be aggregated to daily, weekly, monthly, seasonal or yearly averages. It is useful for identifying recurrent congestion locations, ranking bottlenecks, and calculating cost of delay. It also has value as a before and after analysis data product. When crossed with incident and work zone data it can be helpful for calculating delay costs and other impacts.
NPMRDS is an immediate improvement over floating car studies, at least in cases where coverage is available, and when the accuracy of the start and end points of the analysis do not require exactness. The volume of data in the NPMRDS is orders of magnitude higher than any floating car study could create.
The data is also incredibly useful for the congestion management planning process. Aggregate yearly averages can be calculated and exported for a region for ranking worst performing segments.
The NPMRDS doesn’t have great coverage for secondary arterials, rural roads, and urban streets which makes fine-grained analyses of those roads difficult. Trying to look at a single day on such roads provides more noise than signal for the data analyst.
Another complicating factor are traffic signals. The stop and go nature of signalized arterials means that segments with one or more signals have up and down averages that can complicate the higher level performance measures such as Excessive Delay and Reliability.
Another issue in the NPMRDS is that the TMC network changes from year to year which can result in comparability issues across years. The TMCs IDs often change, and the segments themselves often change in length, sometimes the start point, sometimes the end point, and sometimes both.
NPMRDS data includes traffic volume AADT data from FHWA, but the AADT data lags two years behind the NPMRDS data. So 2020 NPMRDS data is accompanied by 2018 AADT data which is something that an analyst needs to account for either by caveat or by some other data processing method such as crosswalking the 2018 NPMRDS to the 2018 AADT, or applying growth factors.