The Highway Performance Monitoring System (HPMS) is a national level highway information system that includes data on the extent, condition, performance, use and operating characteristics of the nation’s highways. The HPMS data is used by the Federal Highway Administration (FHWA) to support the biennial Condition and Performance Reports to Congress, as well as the annual Highway Statistics publications.
Each State is required to submit data to the Federal Highway Administration (FHWA) by June 15 of each year. The June submittal covers data for the previous calendar year and includes Oregon´s Certified Mileage for the year. Thus, the submittal in June 2010 was data as of December 31, 2009. The data from HPMS is used by Congress for the biannual Condition and Performance Report and is a portion of the federal aid allocation process. It is also used by the Highway Economic Reporting System (HERS) and other national research groups, as well as by ODOT and other local agencies to assist in decision making processes.
The HPMS Submittal includes limited data on all public roads, more detail on selected samples on the Arterial and Collector functional systems, and statewide summary information. The sampling process allows ODOT to gather data on a limited number of samples, but still represent the entire universe. We currently have over 2200 samples with 100% of the Interstates and Freeway/Expressways sampled. Samples on the rest of the Arterials and Collectors have expansion factors. These factors represent the ratio of universe mileage to sample mileage for a category of roads. When the data from samples is expanded, it provides us the chance to create summaries of data about various road systems. The additional sample data provides more detail about traffic, pavement, and geometrics.
The table below shows the State of Oregon’s Certified Public Mileage since 1979. The Federal Highway Administration defines a public road as: “Roads under the jurisdiction of and maintained by a public authority which are open to travel by 2 wheel drive passenger vehicles” (paraphrased). 23 U.S.C. 315, 402(c). The drop in mileage between 1984 and 1985 is primarily due to the U.S. Forest Service closing many miles of their roads to the public. The drop in mileage between 1993 and 1994 was due for the most part to a change in BLM mileage being reported. Most of the drop in mileage between 2006 and 2007 is due to a change in reported mileage from the Oregon State Forest Service and the US Forest Service mileage. The 2000 to current mileage does not include BLM mileage as per a federal ruling.
There are five Summary datasets to be submitted each year. These datasets provide summarized information for a defined area and supplement the more detailed section data. These five summaries are:
1. Statewide Summaries
Statewide summaries describe the demographic, system length and daily vehicle miles traveled (DVMT) total estimates for the Small Urban and Rural public roads that are functionally classed as rural minor collectors or local. Small Urban areas are delimited by the Federal Aid Urban Transportation Boundary (FAUB) and that are between 5,000 and 50,000 in population. Rural areas encompass everything not within the FAUB.
2. Urban Area Summaries
Urban area summaries describe the demographic, system length and DVMT estimate for all functionally classified local roads within the FAUB areas with a population greater than 50,000. Oregon has seven urbanized areas. They are Portland-Metro, Salem-Keizer, Eugene-Springfield, Medford, Bend, Corvallis and Rainier. Rainier is included because it is considered to be part of the Longview, Washington urbanized area. Beginning with 2014 data, three new Urbanized areas will be added – Albany, Grants Pass, and Milton-Freewater (part of Walla-Walla, WA).
3. Vehicle Summaries (Travel activity by vehicle type)
The state estimates percentages of vehicles in each of FHWA´s thirteen vehicle classes for each functional classification. The estimates are built from approximately a few hundred counts that are done on a three year cycle and then summarized into functional system groups and vehicle types. The vehicle groups are motorcycles, passenger cars, light trucks, buses, single-unit trucks, and combination-unit trucks.
4. County Summaries
The county summaries dataset contains the system length data for all roads functionally classed as rural minor collector or local and is stratified by the ownership and urban code.
5. NAAQS Summaries (National Ambient Air Quality Standard)
The final summary dataset contains the system length and travel data for all roads functionally classed as rural minor collector or local that are within an EPA Non-Attainment or Maintenance Area, and the relative pollutant standard. Currently, Oregon has two NAAQS areas - Oakridge and Klamath Falls.
Statewide pavement estimates are provided to be used as default inputs for FHWA’s pavement deterioration models. These estimates are stratified by functional classification, urban or rural, and whether it is on or off the State Highway system. Examples of pavement data types in this summary are thickness of rigid and flexible pavements, base types, joint spacing, and binder types.
Metadata within HPMS is used to describe data collection procedures and post-processing, primarily on traffic and pavement data that may impact the consistency or quality of the data. Metadata applies to an entire data item or group of data items and not to any single data item entry. Examples of traffic metadata items include the percent of actual counts for the reported year, the number of permanent and portable count sites, seasonal/day-of-week/axle/growth factors and type of counts. Examples of pavement metadata include the type of equipment used to collect IRI/rutting/faulting, collection intervals, and method of collection. The final two metadata items describe ramp termini and ramp traffic estimation procedures.
The data items that describe in more detail the section data for road segments can be divided into six categories. These categories, and brief descriptions, are:
1. Inventory: these data items describe the general system information about a road. Included in this category is functional classification, urban/rural code, ownership, lane information (through lanes, turn lanes, HOV etc), speed limit, and toll information.
2. Route: this information describes the assigned route and route qualifier of a road. IE, is it an Interstate, US, USFS, etc, and if the segment has any qualifiers attached (Business, Spur, etc).
3. Traffic: Traffic data is one of the most crucial elements of the HPMS data. It includes Annual Average Daily Traffic (AADT) for all functionally classed roads and on samples, the additional items of AADT for single and combination trucks, peak percents for trucks, Future AADT, K-factors, Directional factors, and intersection control data (signal information, number of stop signs, etc.)
4. Geometric: These data items describe the geometry of the roadway and other items that affect capacity. Examples are lane widths, median and shoulder types and widths, peak parking, curve and grade data, terrain, and obstacles to widening.
5. Pavement: Pavement data items describe the construction and condition of the road and includes items such as IRI (International Roughness Index), PSR (Pavement Service Rating), surface type, rutting, year of last construction or overlay, base type, and thickness of the surface and base. Also included here are climate zone and soil type, which are assigned by FHWA.
6. Special Networks:
There are several special categories of road networks defined in the US Code of Federal Regulations (CFR):
- National Highway System (NHS): A road network of nationally significant roads approved by Congress as required by the Intermodal Surface Transportation Efficiency Act (ISTEA) of 1991. The NHS includes Intermodal Connectors, which are roads that provide service to major intermodal terminals. Congress approved the MAP-21 transportation legislation in 2012, which added all Principal Arterials to the NHS system.
- Strategic Highway Network (Strahnet): A network of highways which are important to the United States’ strategic defense policy and which provide access, continuity and emergency capabilities for defense purposes.
- National Truck Network (NN): A network of highways designated for use by large trucks.
Functional classification (FC): The functional classifications are: Interstate, Other Freeways and Expressways, Other Principal Arterial, Minor Arterial, Major Collector, Minor Collector, or Local. For many data items, FC and Rural/Urban designation is the basis for whether the item is required or not.
Jurisdiction: This code gives the level of ownership for the road. HPMS must include roads of all public entities, whether state, county, city, federal, or several other possibilities. State and federal are broken into several sub-categories.
The HPMS samples are inventoried on a three year schedule. Teams go each year to selected counties gathering information across and along each sample. Typical samples are between 0.3 and 10.0 miles long in rural areas, and between 0.1 and 3.0 miles long in urban areas. Staff members measure lanes, medians, and shoulders. We check pavement type and condition. We note parking, intersections, speed signing and signalization. Some changes signal the need to report improvements. FHWA supplies a field manual showing how to code the data collected. The field trips are often the only way for state staff to find out about changes on other jurisdiction´s roads, such as changing from one-way to two-way.