U.S. Department of Transportation
Federal Highway Administration
1200 New Jersey Avenue, SE
Washington, DC 20590
202-366-4000
Table number footnotes guide.
HM10 | HM12 | HM14 | HM15 | HM16 | HM18 | HM30 | HM31 | HM33 | HM35 | HM36 | HM37 | HM39 | HM40 | HM42 | HM44 | HM47 | HM48 | HM49 | HM50 | HM51 | HM53 | HM55 | HM57 | HM59 | HM60 | HM61 | HM63 | HM64 | HM71 | HM72 | HM80 | HM81 | VM2 | VM3
HM-10: Public Road Length Miles By Ownership
1/ Prior to 1999, municipal was included with other jurisdictions.
2/ Includes State park, State toll, other State agency, other local agency and other roadways not identified by ownership.
3/ Roadways in Federal parks, forests, and reservations that are not part of the State and local highway systems.
HM-12: Public Road Length Miles By Type Of Surface And Ownership/Functional System National Summary
1/ Includes the 50 States, the District of Columbia and Puerto Rico. Some differences from other tables may be noted because these are estimated from sample and summary data; samples entirely on structures are not included. Due to conversion from English to metric units and to rounding, individual cell values may not agree with corresponding mileage table cell values.
2/ Paved includes the following categories: Low Type-- an earth, gravel, or stone roadway which has a bituminous surface course less than 1" thick" suitable for occasional heavy loads; Intermediate Type-- a mixed bituminous or bituminous penetration roadway on a flexible base having a surface and base thickness of less than 7" High-Type Flexible-- a mixed bituminous or bituminous penetration roadway on a flexible base having a combined surface and base thickness of 7" or more; also includes brick, block, or combination roadways; High-Type Composite-- a mixed bituminous or bituminous penetration roadway of more than 1" compacted material on a rigid base with a combined surface and base thickness of 7" or more; High-Type Rigid-- a Portland Cement Concrete roadway with or without a bituminous wearing surface of less than 1".
3/ Prior to 1999 included other State agency roads.
HM-14: Federal-Aid Highway Length Miles By Ownership
1/ Prior to 1999, municipal was included with other jurisdictions.
2/ Includes State park, State toll, other State agency, other local agency, and roadways not identified by ownership.
3/ Roadways in Federal parks, forests, and reservations that are not part of the State and local highway systems.
HM-15: Federal-Aid Highway Length Miles By Ownership
1/ Due to conversion from English to metric units and to rounding, individual cell values may not agree with corresponding mileage table cell values.
HM-16: Public Road Length Miles By Ownership and Federal-Aid Highways National Summary
1/ Includes the 50 States, the District of Columbia, and Puerto Rico. Due to conversion from English to metric units and rounding, individual calls may not agree with corresponding mileage table cell values.
2/ Prior to 1999, municipal was included with other jurisdictions.
HM-18: Public Road Length Miles By Functional System And Federal-Aid Highways National Summary
1/ Includes the 50 States, the District of Columbia and Puerto Rico. Due to conversion from English to metric units and to rounding, individual cell values may not agree with corresponding mileage table cell values.
HM-20: Public Road Length Miles By Functional System
1/ Due to conversion from English to metric units and to rounding, individual cell values may not agree with corresponding mileage table cell values.
HM-30: National Highway System Length Miles Open and Not Open to Traffic
1/ Due to conversion from English to metric units and to rounding, individual cell values may not agree with corresponding mileage table cell values.
HM-31: Federal-Aid Highway Length Miles By Type Of Surface
1/ Some differences from other tables may be noted because these are estimated from sample data; samples entirely on structures are not included.
2/ Paved includes the following categories: Low Type, an earth, gravel or stone roadway which has a bituminous surface course less than 1" thick--suitable for occasional heavy loads; Intermediate Type, a mixed bituminous or bituminous penetration roadway on a flexible base having a combined surface and base thickness less than 7"; High-Type Flexible, a mixed bituminous or bituminous penetration roadway on a flexible base with a combined surface thickness of 7" or more--also includes brick, block or combination roadways; High-Type Composite, a mixed bituminous or bituminous penetration roadway of more than 1" compacted material on a rigid base with a combined surface and base thickness of 7" or more; High-Type Rigid, a Portland Cement Concrete roadway with or without a bituminous wearing surface of less than 1".
HM-33: Federal-Aid Highway Length Miles By Lane Width
1/ Some differences from other tables may be noted because these are estimated from sample data and samples entirely on structures are included.
HM-35: Federal-Aid Highway Length Miles By Traffic Lanes And Access Control
1/ Some differences from other tables may be noted because these are estimated from sample data and samples entirely on structures are not included. Differences may exist from prior years due to the redefinition of divided and undivided roadways in 1999.
2/ Includes 3-lane roadways, one-way streets, undivided multi-lane highways, etc. for Interstate, includes some 2-lane roadways.
HM-36: Federal-Aid Highway Length Miles By Traffic Lanes And Access Control National Summary
1/ Includes the 50 States, the District of Columbia, and Puerto Rico. Due to conversion from English to metric units and to rounding, individual cell values may not agree with corresponding mileage table cell values.
2/ Some differences from other tables may be noted because these are estimated from sample data and do not include samples entirely on structures.
3/ Differences may exist from prior years due to the redefinition of divided and undivided roadways in 1999.
HM-37: Federal-Aid Highway Length Miles By Average Daily Traffic Volume
1/ Some differences from other tables may be noted because these are estimated from sample data and samples entirely on structures are included
HM-39: Federal-Aid Highway Length Miles By Lane Width, Access Control, And Average Daily Traffic Volume National Summary
1/ Includes the 50 States, the District of Columbia, and Puerto Rico. Some differences from other tables may be noted because these are estimated from sample data and do not include samples entirely on structures.
2/ Differences may exist from prior years due to a redefinition of divided and undivided roadways in 1999.
HM-40: National Highway System Road Length Miles By Ownership
1/ Prior to 1999, municipal was included with other jurisdictions.
2/ Includes State park, State toll, other State agency, other local agency, and other roadways not identified by ownership.
3/ Roadways in Federal parks, forests, and reservations that are not part of the State and local highway systems.
HM-42: National Highway System Length Miles By Volume-Service Flow Ratio
1/ In 2001, updated capacity (service flow) calculation procedures were instituted in the HPMS data reporting process. The procedures are based on the Highway Capacity Manual 2000, published by the Transportation Research Board. For multilane facilities volume-service flow ratio is determined by dividing the peak traffic in the peak direction by the capacity. For all other facilities the ratio is determined by dividing the peak traffic by the capacity. Peak traffic is estimated as AADT *K, where K is the design hour volume (30th highest hour) as a percent of AADT. Some differences from other tables may be noted because these are estimated from sample data and do not include samples entirely on structures.
HM-43: National Highway System Lane-Length Lane- Miles By Functional System
1/ Rural minor collector and rural/urban local functional system lane Miles estimated by FHWA assuming two as the number of lanes.
HM-44: National Highway System Travel Annual Vehicle- Miles By Functional System
1/ Travel for all systems are FHWA estimates based on State provided HPMS data.
HM-47: National Highway System Length Miles By Measured Pavement Roughness
1/ Data are reported as the International Roughness Index (IRI) in inches per mile. Reference: World Bank Technical Paper Number 46, 1986. Lower IRI represents smoother riding roadways. To obtain a comprehensive assessment of pavement condition, additional measures of pavement distress are needed.
2/ May include sections entirely on structures and unpaved miles.
HM-48: Federal-Aid Highway Lane - Length Lane- Miles By System
1/ May see differences from prior years; starting in 1999, number of lanes is coded for all systems except rural minor collector and rural/urban local. Rural minor collector and rural/urban local functional system lane- Miles estimated by FHWA assuming two as the number of lanes.
HM-49: Strategic Highway Corridor Network (STRAHNET) Length Miles By Interstate And Non-Interstate
1/ The STRAHNET includes highways which are important to the United States strategic defense. They provide defense access, continuity, and emergency capabilities for the movement of personnel, materials, and equipment.
HM-50: Functional System Length Miles By Ownership
1/ Prior to 1999, municipal was included with other jurisdictions.
2/ Includes State park, State toll, other State agency, other local agency, and roadways not identified by ownership.
3/ Roadways in Federal parks, forest, and reservations that are not a part of the State and local highway systems.
HM-51: Functional System Length Miles By Type Of Surface
1/ Some differences from other tables may be noted because these values are estimated from sample data and do not include samples entirely on structures.
2/ Paved includes the following categories: Low Type, an earth, gravel, or stone roadway which has a bituminous surface course less than1" thick--suitable for occasional heavy loads: Intermediate Type, a mixed bituminous or bituminous penetration roadway on a flexible base having a combined surface and base thickness of less than 7"; High-Type Flexible, a mixed bituminous or bituminous penetration roadway on a flexible base with a combined surface thickness of 7" or more--also includes brick, block, or combination roadways; High-Type Composite, a mixed bituminous or bituminous penetration roadway of more than 1" compacted material on a rigid base with a combined surface and base thickness of 7" or more; High-Type Rigid, a Portland Cement Concrete roadway with or without a bituminous wearing surface of less than 1".
HM-53: Functional System Length Miles By Lane Width
1/ Some differences from other tables may be noted because these are estimated from sample data; samples entirely on structures are included.
HM-55: Functional System Length Miles By Traffic Lanes And Access Control
1/ Some differences from other tables may be noted because these are estimated from sample data; samples entirely on structures are not included.
2/ Differences may exist from prior years due to the redefinition of divided and undivided roadways in 1999.
3/ Includes 3-lane roadways, one-way streets, multi-lane 4-lane highways, etc.; for Interstate includes 2-lane roadways.
HM-57: Functional System Length Miles By Average Daily Traffic Volume
1/ Some differences from other tables may be noted because these values are estimated from sample data; samples entirely on structures are included.
HM-59: Functional System Length Miles By Lane Width, Access Control And Average Daily Traffic Volume National Summary
1/ Includes the 50 States, the District of Columbia and Puerto Rico. Some differences from other tables may be noted because these are estimated from sample data; does not include samples entirely on structures.
2/ Differences may exist from prior years due to the redefinition of divided and undivided roadways in 1999.
HM-60: Functional System Lane-Length Lane- Miles
1/ Due to conversion from English to metric units and to rounding, individual cell values may not agree with corresponding mileage table cell values. May see differences from prior years, stating in 1999, number of lanes is coded for all systems except rural minor collector and rural/urban local.
2/ Rural minor collector and rural/urban local functional system lane miles estimated by FHWA assuming two as the number of lanes.
HM-61: Functional System Length Miles By Volume-Service Flow Ratio
1/ In 2001, updated capacity (service flow) calculation procedures were instituted in the HPMS data reporting process. The procedures are based on the Highway Capacity Manual 2000, published by the Transportation Research Board. For multilane facilities volume-service flow ratio is determined by dividing the peak traffic in the peak direction by the capacity. For all other facilities the ratio is determined by dividing the peak traffic by the capacity. Peak traffic is estimated as AADT *K, where K is the design hour volume (30th highest hour) as a percent of AADT. Some differences from other tables may be noted because these values are estimated from sample data and do not include samples entirely on structures.
HM-63: Functional System Length Miles By Measured Pavement Roughness/Present Serviceability Rating
1/ Some States elect to report International Roughness Index (IRI) for these systems; some report IRI for some sections and PSR for some sections. Some differences from other tables may be noted because these are estimated from sample data.
2/ Data are reported as the IRI in inches per mile. Reference: World Bank Technical Paper Number 46, 1986. Lower IRI represents smoother riding roadways; to obtain a comprehensive assessment of pavement condition, additional measures of pavement distress are needed.
3/ The "Present Serviceability Rating" (PSR) is a subjective, primarily ride-based system adapted from the "AASHO ROAD TESTS" conducted in the late 1950's and early 1960's. Reference: Highway Research Board Special Report 61E, 1962. The PSR values range from 0.1 to 5.0; higher PSR values represent smoother riding roadways.
HM-64: Functional System Length Miles By Measured Pavement Roughness
1/ Data are reported as the International Roughness Index (IRI) in inches per mile. Reference: World Bank Technical Paper Number 46, 1986. Lower IRI represents smoother riding roadways; to obtain a comprehensive assessment of pavement condition, additional measures of pavement distress are needed.
2/ May include sections entirely on structures and unpaved miles.
3/ Estimated from sample data.
HM-71: Urbanized Areas Miles And Daily Vehicle- Miles Of Travel
1/ A "Federal-Aid Urbanized Area" is an area with 50,000 or more persons that at a minimum encompasses the land area delineated as the urbanized area by the Bureau of the Census. Urbanized areas which have been combined with others for reporting purposes are not shown separately. Areas are in sort by population.
2/ Shaded where data not available.
HM-72: Urbanized Areas Selected Characteristics
1/ A "Federal-Aid Urbanized Areas" is an area with 50,000 or more persons that at a minimum encompasses the land area delineated as the urbanized area by the Bureau of the Census. Urbanized areas which have been combined with others for reporting purposes are not shown separately. Areas are in sort by population.
2/ "DVMT" stands for "Daily Vehicle-Miles of Travel." Shaded where data not available.
3/ Lane-miles estimated by FHWA.
HM-80: State Highway Agency-Owned Public Roads Miles By Functional System
1/ Includes roadways owned by the State highway agency. Excludes roadways owned by State toll, State park and other State agencies.
HM-81: State Highway Agency-Owned Public Roads Rural And Urban Miles; Estimated Lane- Miles And Daily Travel
1/ Includes roadways owned by the State highway agency. Excludes roadways owned by State toll, State park and other State agencies.
2/ Statewide totals for miles, lane-miles, and travel are found in tables HM-20, HM-60 and VM-2 (annual VMT), respectively.
3/ May see differences from prior years; starting in 1999, number of lanes is coded for all systems except rural minor collector and rural/urban local, which are assumed to have two lanes.
4/ DVMT (Daily Vehicle-Miles of Travel) is in thousands.
5/ AADT means Annual Average Daily Traffic. ADDT/Lane is a statewide average.
VM-2: Functional System Travel Annual Vehicle- Miles
1/ Travel for all systems are FHWA estimates based on State provided HPMS data.
VM-3: Federal -Aid Highway Travel Annual Vehicle- Miles
1/ Travel for all systems are FHWA estimates based on State provided HPMS data.
If you have specific questions regarding Mileage and Travel, email us or phone (202) 366-0160.
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