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HPMS Questions and Answers
HPMS and Census 2000
Question: How should the 2001 HPMS data be reported?
Answer: Existing urbanized and small urban boundaries should be used to report the 2001 HPMS data due in June 2002. Population numbers for the rural, small urban and individual urbanized areas should be developed from the Census estimate of State population as of July 1, 2001. This is in accordance with standard reporting practice noted on page III-2 of the HPMS Field Manual.
Question: How should the 2002 HPMS data be reported?
Answer: Consistent with guidance provided in a recently released Frequently Asked Questions document, www.fhwa.dot.gov/planning/census/faqa2cdt.htm, States can choose to adopt the Census 2000 designated boundaries as is or make minor adjustments to those boundaries as long as they encompass at least the Census designated areas. HPMS data should be reported in accordance with the State boundary decision starting with 2002 data reported in 2003, or at the earliest possible time after a State decision is made on any boundary changes. If the boundaries are changed from the existing boundaries, the State will need to do a functional reclassification of roads and an assessment of sample adequacy within the new urbanized area boundaries. The 5000-person population figure is retained for the purposes of defining the small urban versus rural break point used in HPMS Data Item 13; for HPMS data reporting purposes, a "small urban area" and an "urban cluster" are taken to have the same meaning. In accordance with the HPMS Field Manual, all urbanized areas must be sampled and reported individually; the reporting of HPMS data for grouped urbanized areas should be discontinued as soon as possible.
Question: Since the population data are collected and reported by the Bureau of the Census, why doesn't FHWA get the data directly from that agency instead of requiring the States to get the data and then report the data to FHWA?
Answer: FHWA asks the States for current year population estimates for rural areas (under 5,000 persons), small urban areas (all urban places of 5,000 or more persons not within an urbanized area), and each Federal-aid urbanized area of the State in HPMS. Current year population data are available from the Census on a county and State level only; therefore, there is no basis for FHWA to estimate the correct rural, small urban, and adjusted Federal-aid urbanized area population splits. We believe that the States or MPO's are in a better position to estimate these splits from available Census data resources.
Census data resources include: Annual county population figures as of July 1 are summed to produce statewide estimates; these are available at the end of each calendar year. Biennial population estimates are produced for places of 100,000 or more persons as well as Metropolitan Areas; they are available several months after the close of the estimate period. Place and County subdivision population estimates for all incorporated places, including cities, towns, boroughs, and villages (depending on which State) are available in the years following a decennial Census; these are done as a "special analysis" on a staff available basis.
Note that each product has a different quality level and availability and that these products do not exactly align with the adjusted area boundaries. Decennial (or special inter-decennial) Census estimates of population and land area based on the latest Census defined boundaries have the highest quality; however, they are normally available only once each decade (2000 data will likely be available in 2002). Census source estimates need to be adjusted if any area boundaries are adjusted.
Estimating percent truck data
Question: How should percent truck data be reported for HPMS sample sections where there is not site-specific data available?
Answer: Every sample section needs to have percent truck data coded; zero should only be coded if there is no truck traffic on the section or if the percent trucks is less than one-half of one percent (result of rounding to nearest whole percent). Zero should not be coded if the percent of trucks is unknown; an estimate of the value should be used instead. Coding only sections for which there is an actual measured value results in too many sample sections with zero trucks; since the HPMS uses a single expansion factor for all variables, this practice distorts the information resulting from the expanded sample.
Where States are collecting data that results in rounded percent truck values of zero, a note in the submittal comment file is appropriate. This may be the case on high volume routes, especially in urban areas, where the volume of trucks may be significant but their percent of total AADT is insignificant.
The preferred way to eliminate this problem over time is to upgrade equipment used for short count purposes to counters that also provide vehicle classification information. Used where needed for short counts on HPMS sample sections, they will permit reporting measured values.
When it is necessary to use an estimate, the State should determine the best way to estimate percent trucks based on the information available. The most credible method is to assign known site-specific values to other samples that are located on the same route. Other methods include assigning known site-specific values to other samples that are located on similar facilities with similar traffic characteristics that are located in the same geographical area and are in the same volume group; or, assigning known site-specific values to other samples that are in the same functional class and are located in the same area type (rural, small urban, urbanized) with similar travel characteristics. Average statewide values calculated by functional class should not be used.
Supplemental methods and sources may be particularly useful in urban areas; some of these include turning movement studies, origin and destination studies, license plate surveys, design estimates and projections, and MPO/municipal data obtained for other purposes. Short-term visual observation of truck travel on a sample section can also be of help in developing an estimate. The HPMS analyst should enlist the assistance of the State traffic engineering or traffic operations unit in developing percent trucks estimates.
Percent of average daily trucks should be reported as an annualized value. This is consistent with the new TMG that has as a goal of traffic monitoring programs the ability to adjust short-term truck data to represent truck AADT. Until States are able to estimate truck AADT values, percent truck data that best represents average conditions should be reported.
Percent of peak trucks should be reported as the proportion of trucks in the traffic stream during the hour or period of peak total traffic flow on the sample section.
HPMS Samples on Realigned Road Sections
Question: If a route is realigned (such as by adding a bypass) and the functional class is moved to the new route, should a sample stay on the old roadway or should it move to a section or segment of the new roadway alignment?
Answer: If a route is realigned, the sample remains with the original route; a sample is never just moved to a new alignment. If the original route is reclassified as a rural minor collector or a local road, then the sample is dropped. If a new sample is needed to meet the sampling requirements for the original functional system and volume group, a new sample must be randomly selected from the available mileage for that functional system and volume group.
HPMS Software
Question: What is the latest version of the HPMS software?
Answer: Version 5.0 of the HPMS software was released in April 2002. This is the version of the software that must be used for the 2001 HPMS submittal in June 2002.
Reporting Pavement Data
Question: How should IRI data (Item 35) older than two years be reported?
Answer: IRI should be remeasured on a two-year cycle; however, retain existing IRI values for sections until they are replaced by new measured values.
Question: What should be coded on a sample section if IRI is not available?
Answer: FHWA needs either an IRI or a PSR value coded for every sample section. On sample sections where IRI is required but not available, a PSR value must be coded instead. If you have coded an IRI, do not also code a PSR; do not report both an IRI and PSR value for any sample section.
Question: How should SN (Item 51) be reported after a pavement improvement is made?
Answer: A new SN should be computed considering the full pavement structure in place after an improvement is made. Thin maintenance overlays, less than 1" thickness, should not trigger a revised SN.
Ferryboats and HPMS
Question: Should public ferryboat routes be included in HPMS and in the Certified Public Road Mileage?
Answer: No. Segments of routes carried on ferryboats should not be included in the HPMS database. They are neither roads nor structures, and are inconsistent with the data and data definitions of the HPMS. Also, segments of routes carried on ferryboats do not meet the legal definition of a "public road" and their length should not be included in the Certified Public Road Mileage reported annually to FHWA.
Metric Reporting
Question: Does HPMS data have to be collected in metric units?
Answer: No. However, the HPMS Submittal Software will convert English data to metric units prior to submittal to FHWA. Software users must be careful to specify which unit is being used, and not mix English with metric.
Coding STRAHNET Routes and Connectors
Question: What routes should be reported in HPMS as being STRAHNET routes?
Answer: Report all open to traffic Interstate routes, U.S. Department of Defense (DOD) designated non-Interstate routes, and primary connector routes to Priority 1 and 2 installations and ports. These are the STRAHNET and connector routes that are on the NHS. If only one connecting route is designated for a facility, that is the primary connector route. Secondary or additional connector routes that are not on the NHS should not be reported in HPMS as STRAHNET. Unbuilt NHS routes must not be reported as STRAHNET routes; all STRAHNET routing must be on open-to-traffic facilities.
Question: Where can I find information on designated STRAHNET routes and connectors?
Answer: Maps of STRAHNET routes and connectors can be found at the official STRAHNET web site: http://www.tea.army.mil/pubs_res/strahnet/strahnet.htm.
A user name and password are needed to enter the site. If you do not already have one, then when a new window opens asking for a username and password, click on the cancel button. The web browser should load a web page that contains information on how to obtain a username and password.
DOD has revised these maps to include only those routes and connectors that serve Priority 1 and 2 military facilities; these routes are on the NHS and need to be reported in HPMS. Note that the network-based lengths shown on the DOD site may not precisely match actual State measured lengths because of data source differences, rounding, etc.
Highway Capacity
Question: Have there been any changes to the HPMS capacity calculation procedures for the 2001 data?
Answer: There are changes in the capacity calculation procedures for the 2001 HPMS data due in June 2002. The HPMS submittal software capacity calculation procedures have been updated to be consistent with the 2000 version of the Highway Capacity Manual (HCM) and are included in Version 5.0 of the HPMS software that was released in April 2002.
If a State has determined override capacity values for some of their HPMS sample segments in the past, and is going to do so again for these segments in the 2001 data, the 2001 capacity estimates must use the procedures outlined in the HCM 2000. The current capacity values in the 2000 HPMS data cannot be carried forward to the 2001 data.
Reporting Nationally Designated Truck Routes
Question: How should nationally designated truck routes be reported in HPMS?
Answer: Data Item 28 requires the identification of nationally designated truck routes. These are defined as the routes designated for use by dimensioned commercial vehicles under the Surface Transportation Assistance Act (STAA) of 1982. Nationally designated truck routes include the Interstate System (a few sections are exempted in Minnesota and Virginia), non-Interstate routes specifically listed in 23CFR658, Appendix A, as amended, and, in the States of Arkansas, Colorado, Indiana, Iowa, Kansas, Louisiana, Mississippi, Montana, Nebraska, Nevada, Ohio, Oklahoma, South Dakota, Texas, Utah, Washington, and Wyoming, the other existing Federal-aid Primary (FAP) routes as defined in 1991. These routes are to be coded as "1" in HPMS Item 28.
Some States have extended the rules to allow STAA dimensioned commercial vehicles to operate on other State routes. These and other non-national truck network roads used between the STAA national network and terminals and facilities for food, fuel, repairs, and rest under the reasonable access rule are not nationally designated truck routes. These routes are to be coded as "0" in HPMS Item 28.
