Highway Performance Monitoring System Field Manual

Chapter 2 HPMS Core Components

2.1 Overview

The HPMS process is designed to be a cooperative effort between the States and the Federal Highway Administration (FHWA). Chapter 1 described the background of the HPMS program and discussed the scope and uses of the national database. The roles and responsibilities of the States and FHWA regarding HPMS were also presented in the previous chapter. This chapter focuses on the States’ responsibilities for collecting the HPMS data and discusses the way in which the data will be used to support the core components of HPMS.

There are three sources of data for the national HPMS database. These include:

1. Data that are to be developed and supplied by the States
2. Data that are obtained by FHWA from other non-State sources
3. Data that are generated or calculated by FHWA

Data that are to be maintained by FHWA are done so in both geospatial and non-geospatial formats, and is available for use by the States for research and analysis, or to help States as they prepare their HPMS submittal. Data that are generated by FHWA are created during the submittal process, and are discussed in Chapter 4 of this manual. Since the purpose of this manual is to assist the States with their data collection and reporting activities, the remainder of this chapter focuses on the types of data that are to be supplied by the States.

The States are responsible for providing the following types of data to FHWA: Full Extent, Sample Panel, Summary, Estimates, and Metadata. The geospatial component of the HPMS data model links the data from these categories to a geographic location on each State’s respective linear referencing system (LRS) network. More information on the geospatial component of the data model can be found in Chapter 3 of this manual.

2.2 Full Extent Data

Within the context of the HPMS system, some data elements must be reported for their full extent (i.e. system-wide). The Full Extent network consists of the National Highway System (NHS) routes (including intermodal connectors) and all other roads, excluding those functionally classified as minor collectors in rural areas and local roads in any area.. Data elements that are reported for these types of roads are referred to as Full Extent data items. For some data items, the Full Extent’s coverage also includes ramps associated with grade-separated interchanges for which a limited number of Full Extent data items are to be reported.

2.3 Sample Panel Data

Within the extent of all Federal-aid eligible roads, a random selection of roadway sections is used to represent various attributes at a system-wide level for the purposes of assessing the performance and condition of the network. This process helps to reduce any burden that may be imposed on the States to perform data collection to meet their HPMS reporting requirements. These sections of the network are referred to as Sample Panel sections. Moreover, the Sample Panel sections are selected randomly and are intended to give a statistically valid representation of the State’s road network. Due to the structure of the HPMS data model (discussed in Chapter 3), the States are not required to extract the Sample Panel data items, as long as the data in their submittal covers the Sample Panel. States are encouraged to submit their entire dataset for each data item. FHWA will dynamically assign values to the Sample Panel sections, using the data provided by the States. This should help to lessen the data processing burden on States that are currently collecting more than the minimum coverage. Additional information on the Sample selection process is provided in Chapter 6.

2.4 Data Items Required for the Full Extent and/or Sample Panel Sections

The data items listed in Table 2.1 are to be submitted as part of the Sections dataset, which will be stored as a table within FHWA’s database. Detailed information for these data items is provided in Chapter 4.

• Item Number is the number assigned to each data item
• Data Item identifies the type of attribute data to be reported
• Extent indicates if the data item is required for the Full Extent (FE), Sample Panel (SP) sections, or the Full Extent and Ramp sections (FE+R)

Table 2.1 Data Items to be Reported

2.5 Summary Data

The summary data are intended to provide general information on the use, extent, condition, and performance of the public roads, particularly on the lower functional systems (minor collectors in rural areas and local roads in any area). For example, non-Federal-aid roads do not require section-level detail and can be summarized from State and local sources. These sources include statewide highway databases, inventory management systems, Intelligent Transportation Systems (ITS), traffic monitoring systems, and data made available from local governments and Metropolitan Planning Organizations (MPOs).

The type of data reported in the summary data includes travel, system length, and vehicle classification by functional system and area type, in addition to land area and population by area type. The area types include rural, small urban, and individual urbanized, non-attainment, and maintenance areas. Pollutant type is also reported as an indicator of air-quality in non-attainment areas.

The following summaries are to be reported as five individual datasets, which will be stored as tables within FHWA’s database:

1. Statewide Summaries
2. Vehicle Summaries
3. Urban Summaries
4. County Summaries
5. NAAQS Summaries

Statewide Summaries

This summary contains information about population, land area (in thousands), and system length (in miles) as it pertains to rural areas, and daily travel (vehicle-miles traveled (VMT) in thousands) with respect to small urban areas. The data for the extent of the road network are further subdivided by the extent of paved and unpaved roads in the rural and small urban areas.

Vehicle Summaries

This summary contains travel activity data summarized by vehicle type and highway system group. The highway system group includes six categories: the first three for rural roads and the last three for urban roads. Each of these categories represents the group for which travel by vehicle type is summarized.

Urban Summaries

This summary contains information about travel, population, and land area for roads functionally classified as local, for each adjusted urbanized area.

County Summaries

This summary contains system length data by county for all roads functionally classified as minor collectors in rural areas and local roads in any area. Any National Highway System (NHS) routes on these roads are also included in this summary for each county. This summary also includes information about the ownership of the roads (public or private), as well as jurisdictional responsibility for the road. Some examples of the types of roads that may be included in this summary are park roads, military roads, toll roads, public roads at an airport, school, or university, and roads under the jurisdiction of the Bureau of Indian Affairs.

NAAQS Summaries

This summary includes system length and travel data for rural minor collectors and rural/urban locals summarized by non-attainment and maintenance areas, and pollutant type. HPMS uses the Environmental Protection Agency (EPA) defined non-attainment or maintenance area for identification purposes.

2.6 Estimates Data

The estimates dataset that is to be submitted will be stored as a table within FHWA’s database. This data will only be used for national-level analysis. The sole purpose of these data is to provide an estimate of current State and local pavement conditions and construction practices where measured data are not available. These data are used for analysis in various FHWA models. Estimated values may be provided for the following pavement-related items:

• Last Overlay Thickness
• Thickness of Rigid Pavement
• Thickness of Flexible Pavement
• Base Type
• Base Thickness
• Binder Type
• Dowel Bar Presence
• Typical Joint Spacing

2.7 Metadata

The metadata that are to be submitted will be stored within FHWA’s database. The purpose of the metadata is to provide additional information for understanding and/or explaining the variability in certain traffic and pavement-related data items that are reported in HPMS. Metadata within HPMS are used to describe data collection procedures and post-processing that may affect the consistency or quality of the data. The metadata contains information related to the collection and reporting of the following:

• Traffic counts
• Vehicle classification
• Source of the travel data
• Type of IRI equipment used to measure the International Roughness Index (IRI)
• Method and equipment used to collect rutting data
• Method and equipment used to collect faulting data
• Method and equipment used to measure pavement cracking
• Pavement distress data reporting format
• Ramp termini descriptions, and traffic estimation method used for reporting traffic data on ramps

Some metadata may be published annually in the Highway Statistics publication, or, are provided to data users as requested. The metadata provided by each State will not be used by FHWA to alter a State’s HPMS submittal.