Wikipedia:WikiProject U.S. Roads/Resources/Lengths

This page is for determining the precise length of a numbered route. The majority of information is to at least two decimal places, so that should probably be a good standard.

ArcExplorer is a good free GIS viewer for the states that use GIS data.

"Show your work" on the talk page of the article if it is complicated - for instance Talk:U.S. Route 30. Always cite the source with a footnote in the article. Or see User:Mxn/Citing a feature in an ArcGIS map

All highways
The National Highway Planning Network GIS data contains many major highways in the US. Be sure when you open the table, the routes (SIGN1 column) are put in order so that the route you want repeats itself at least twice in the table. Scroll right, and then you will see a MILES column. Add up every instance of the route in this column, and then you will get the total length. It is usually more complicated because of overlaps, and there can be errors (like a repeated length on US 50 east of Bedford, IN).

Interstates
The FHWA Route Log and Finder List includes mileages by state. Be careful on routes with concurrencies - the numbers after taking into account the concurrency may not be precise. If possible use the information from one of the states.

Alabama
The Milepost maps can be used to get mileposts for Alabama routes. Maps are by county, but a cumulative total of miles is given if you follow from county to county.

Arizona
The 2009 Arizona State Highway System Log] can be used for all route lengths. Also other years are available 2008, 2007, 2006, 2005, and 1998

Arkansas
The Arkansas State Highway and Transportation Department Database can be used for all route lengths. In Arkansas, there are almost no concurrencies, the more major route takes priority and the mileage is NOT included again for the smaller route, even if it is a signed concurrency. The 2010 data (added to the site on June 8, 2011) now includes some projected lengths and mileages for on/off ramps. Neither were included in the 2009 data.

California
The Caltrans bridge log includes milepost information. Watch for milepost equations - points where the mileposts jump due to realignments.

Colorado
Use the Highways Data; the TCORIS Coding Records Reference File shows city limits.

Connecticut
Connecticut has the Highway Log for Interstates, US routes, and state routes.

Delaware
Delaware has the Traffic Count and Mileage Report for Interstates, US routes, and state routes.

Florida
Florida has an Interchange Report for all Interstate Highways and other expressways. Straight-line diagrams (SLDs) are available for all Interstate and U.S. Highways, State Roads, and County Routes (organized by county). Note that various parts of some highways may be assigned different reference numbers within the same county, whether or not they are continuous segments (especially if highways are concurrent with one another). Some highways may have various SLDs in the same county for this reason.

Georgia
Georgia has GeoTRAQS and a GeoTRAQS Tutorial can be found here. (needs Microsoft Silverlight)

Hawaii
Hawaii has GIS scroll down "PHYSICAL FEATURES / BASEMAP LAYERS" and download the shapefile for any "Roads", the best for length is "Roads - State County Routes (State Dot)".

Idaho
The milepost log includes milepost information. Watch for milepost equations - points where the mileposts jump due to realignments.

Illinois
Illinois has GIS data, including begin and end milepost fields for each segment. If desired, use the unique values option to show the route as a specific color and a wider line. Be careful at concurrencies and other places where the sequence might change. They have a PDF listing Interstates only - it probably agrees with the FHWA data but I haven't checked.

See WikiProject U.S. Roads/Resources/Lengths/Illinois for a working list of counties and U.S. and state route names and distances.

Indiana
Indiana has a reference post book (RPB) that is for every state maintained road in 2004. The reference post book goes to two decimal places. For a concurrency the book will have the lower number of the higher class. For example to find the mileposts of US 30, around Fort Wayne, you need to look at US 30, I–69, I–469, and US 30. Another example is finding the mile posts for SR 67, near Worthington, one would need to look at US 231. Roads that have been decommission, moved, or extended, after 2004, will not be changed. For intersections or interchanges during a concurrency please see this page, for how to calculate them.

Iowa
Iowa has GIS data dating back to 1998. In each year, you can download information county-by-county. The statewide folder contains the same data as the latest year, but in one large file. Download ROAD_INFO, DIRECT_LANE and COUNTY_BORDERS_SO. If desired, use the unique values option to show the route as a specific color and a wider line. Find the last segment in each county and find the BEGINLRD value in ROAD_INFO and the LANELENG value in DIRECT_LANE, and add them.

There is also the traffic book, which gives detailed AADT and length data (to three decimal places). The traffic book gives the complete lengths of rural and municipal segments of highways. You'll have to add the two figures to get the complete length. To find the junctions, it's easiest to copy and paste the traffic book information into a spreadsheet.

For GIS data and the traffic book, be careful at concurrencies. The Iowa DOT only counts a segment once even if more than one route follows the road. The traffic book gives precedence to the highest-class highway with the lowest number (I-35 → I-80 → US 30 → US 218 → Iowa 3 → Iowa 415). If the route overlaps another route, there will be a line saying DUPLICATE ROUTE &lt;route&gt;. You will have to add in the corresponding segments to get the complete length.

Kansas
Kansas has reports, select the "CSR2012_D#." (note: D# equals the needed district, 1 through 6.)

Kentucky
Kentucky has Official DMI Route Log select by district or county.

Maine
Maine has GIS for Interstates, US Routes, State Routes, and some local streets. Scroll to bottom of page and download the shape file "Roads - DOT (MEDOTPUBRDS) (mouth/day/year)" (the right icon).

Maryland
WikiProject Roads in Maryland/Highway Location Reference: This page provides access to the HLRs for all 23 counties between 1999 and 2018. There is also an HLR for Baltimore City for 2005. Use these documents for all mileage information on existing highways or highways removed from the state system from 1999 onwards.

Massachusetts
New

Massachusetts has MassGIS Data, download either by county or the whole state. If someone downloads the whole state you would need the "Shapefiles" for use with QGIS; for a county click the link next to county's name.

Old

(Keeping in case anyone downloaded before the page was removed.)

Quoted from SPUI's comments on my talk page:

It's a bit complicated. (This is assuming you have Microsoft Access; it may work slightly differently in other programs.) Download the Road Inventory Geodatabase and open it. Make a new query with the following fields: Once the query loads, scroll down to the route you want, and find the last entry in the northbound or eastbound (increasing) direction. That will give you the mileage. (Unless the route ends concurrent with another - I'm not sure if any do that, though some do begin concurrent, which isn't a problem.)
 * ROUTENUMBER ascending, criteria >="1" (to eliminate unnumbered roads)
 * ROUTEDIRECTION
 * ROUTEFROM ascending
 * ROUTETO
 * Other possibly useful fields are ROUTESYSTEM, CITY, STREETNAME, FROMSTREETNAME and TOSTREETNAME. Note that the from and to streets are not for the section that is numbered, but for the whole street, so make sure to check against mileage if you have issues with finding the exact end.

Tckma 20:03, 31 July 2006 (UTC)

Michigan
The Michigan Department of Transportation published the current edition of the Control Section Atlas and Physical Reference Finder in 2009. By adding the lengths of the various control sections of a highway in each of the counties in which it passes, the overall length can be computed. A more useful tool is the Physical Reference Finder Application, which is a mapping tool that can be used to gain a finer level of detail on control section lengths. It can be used to calculate intermediate mile posts for all state highways and many county roads. Both tools are accurate to the thousandth of a mile, so three decimal places should be given in resulting computations.

Minnesota
Minnesota has Roadway Data in Excel format, WARNING it takes some time to load, probably not the best on older computers.

Mississippi
Mississippi has the Mississippi Public Roads Selected Statistics which lists the total mileage for Interstates, US, and state highways, not factoring in concurrences.

Missouri
Flex Map Viewer Do a "text search" for the route you want and it will give you both directions of the route and mileposts for every junction.

Montana
2011 route log

Route numbers do not necessarily line up with sections in the log. To find out which section you need, check out the map and look for the N-# or P-#. Once you know that number, you can use the log above.

Nebraska
Nebraska has the Nebraska Highway Reference Log Book which includes mileposts for Interstate, US, and state highways.

Nevada
Nevada documents the total length of their routes at State Maintained Highways of Nevada, Descriptions and Maps, as well as lengths by county (and Carson City). When using this book, one must account for the following: Older versions of the book (prior to 2012) also show some milepost locations in their maps—milepost references are not comprehensive, although mileposts at termini and where routes cross county (and some city limit) lines are almost always shown.
 * U.S. route overlaps on other US or Interstate routes. Only one of the overlapping highways will show mileage along the overlap, although the overlapping section is usually listed separately from the remaining mileage.
 * In some cases, the log may reflect mileage on a future/planned alignment not yet open to traffic. Mileage for the open route may follow another state highway.

New Jersey
New Jersey is by far the easiest I've found - simply open their straight line diagrams and go to the appropriate route, making sure to take into account concurrencies at the end of the route.

New Mexico
New Mexico has Statewide mileposts, zoom way in on the pdf, also AADT, with milepost.

New York
New York provides mileages for every state route, touring and reference, in their annual Traffic Data Report. Appendix E (in the back of the report) contains the mileages of every route by segment. Simply add the mileages together to get the cumulative route length.

North Carolina
The Straightline Diagrams have mileage and construction history for Interstates, US routes, and NC routes. The mileposts reset at county lines. Currently, only the Interstates are available online.

Also

North Carolina has GIS Data Layers, under Road Data, download "Road Characteristics Arcs Shapefile Format", this file is release every quarter and can be used on Interstate, US routes and NC routes.

North Dakota
Contact User:Detcin North Dakota two has a pdf map, one is the whole state, the other is details of some areas. User:Detcin will forward the pdfs on request or you could email North Dakota Department of Transportation and ask nicely for the information.

Ohio
Ohio has straight line diagrams cut by county. Watch for milepost equations - points where the mileposts jump due to realignments.

Oklahoma
Oklahoma has GIS Data, download "Highway".

Oregon
Oregon has straightline charts for highways the currently exist. In addition to current highways, lengths for highways that were decommissioned or transferred to local control after 2001 may be found on the digital video log. Both methods use ODOT's internal highway names and numbers, so make sure to get the right highway numbers using the routes to highway cross reference. Also be careful of milepost equations - points where the mileposts jump due to realignments.

Pennsylvania
Pennsylvania has GIS data for state-maintained roads. The shapefile is very large, thus some lower-end computers will have problems processing the file. For those that can, the four relevant columns in the data are "ST_RT_NO", "SEG_LGNTH_", "NLF_CNTL_B", and "NLF_CNTL_E". "ST_RT_NO" is the four-digit state route designation assigned by the Pennsylvania Department of Transportation; consult the PennDOT county maps for the appropriate number for the route, but most times the number is just the number of the signed designation prefixed by one to three zeroes. "SEG_LGNTH_" is the length of the data segment in feet. "NLF_CNTL_B" is the milepost of the data segment's beginning in feet. "NLF_CNTL_E" is the opposite; it is the milepost of the data segment's endpoint in feet. Thus, to quickly determine the length of a route, simply convert the "NLF_CNTL_E" value of the last (northern or easternmost) segment of the route from feet to miles (divide by 5280).

Be careful of areas where the route is a divided highway; both directions will have entries in the data in this instance, making it necessary to skip/toss out the mileage of the westbound and northbound portions in order to obtain an accurate length. Overlaps are also an issue; only the "lower-numbered" route has segment data (as an example, the mileage of the US 6 [SR 0006] and PA 434 [SR 0434] overlap is listed only for US 6 and not for PA 434). Be sure to account for both issues when calculating route lengths from the GIS data.

Rhode Island
Rhode Island has Highway functional classification.

South Carolina
South Carolina has GIS for Interstates, US routes, and SC routes. On the right click "GIS Files" then in the center click "Select Shape File". Finally click and download "STATEWIDE HIGHWAY 2012.zip", unzip and open in QGIS or another GIS software.

South Dakota
South Dakota has Pavement Condition Monitoring in pdf format.

Also South Dakota has a DOT Viewer here is a tutorial on how to use it.

Tennessee
AADT maps show lengths to one decimal place. There are lots of inset maps for cities.

Texas
The TxDOT Highway Designation Files are probably your best source for Texas road-length information. At the top of the page for a given road is its' certified mileage, and an as-of date.

Utah
Utah has Highway Referencing select the route desired.

Vermont
Vermont is an interesting case as state highways maintained by the town (known officially as "state-numbered town highways") are treated in route logs and documents as essentially a separate system than state-maintained routes. For routes state-maintained along their entire length, simply consult the Route Log for State Highways and add up the segments. Like in Pennsylvania, if a lower-numbered route overlaps a higher-numbered route, the mileage is listed only for the lower-numbered route, although some situations exist where this is reversed (example: the VT 11/103 overlap is logged in VT 103's segment data instead of VT 11). Be sure to account for these situations.

For routes partially or wholly maintained by towns, finding lengths becomes much more difficult. If the route is a "Major Collector"—one with a MC designation under 326—it will be listed in the Town Highway Major Collectors log available at the link above. Look for the route number ("VT#") in the name column. If it is a "Minor Collector"—which can be determined by consulting the Rural Functional Statewide Map available at this page (near the very bottom)—the only resource for lengths that I've found to date are the VTrans town highway maps. Consult the map of the town that the route is in, then add up the distances shown along the route.

Please note that the state highway log has a distance precision of three digits while all other VTrans resources have only two. Thus, if the state highway log is combined with any other resource to create a total distance, the total should be given only to two digits to avoid false precision.

Virginia
The Virginia Department of Transportation (VDOT) maintains a series of AADT documents. All roads in these documents have length information by road segment.. This information is complete for all interstate, US, and Virginia state primary routes. Because of the nature of the Virginia secondary route system, information on secondary routes / certain streets is missing or incomplete for Arlington County, Henrico County, many incorporated towns, and all independent cities.

The one thing one has to be careful about is duplicated information. Example: there is a stretch of I-66 in Prince William County that is concurrent with SR 234. In the AADT document, this information appears as both I-66/SR 234 and SR 234/I-66. Also, many divided highways have different lengths depending upon the direction.

Examples of AADT documents:

Loudoun 2008 AADT

Prince William 2008 AADT

Fairfax 2008 AADT

Washington
WSDOT publishes an annual State Highway Log, usually around early March, dating back to 2001. Use WSDOT State Highway Log to cite them.

West Virginia
West Virginia has gis, the whole state or interstate, U.S. Routes, or the state route can be download.

Wyoming
The Maintenance Section Reference Book includes milepost information. Also reference marker book (archive link) can be used for milepost infomation, be sure to use the right column.