SLD ReadMe


The Ohio Department of Transportation (ODOT) State Roadway System consists of 19,257 miles of highway in 88 counties. There are 1,332 miles on 22 Interstate routes.  The 47 U. S. routes encompass 3,911 miles.  Lastly, over 600 State Routes cover 14,014 miles.  The Roadway Information section, in the Office of Technical Services, is responsible for maintaining the highway inventory records for these routes.

A Straight Line Diagram (SLD) is a two dimensional graphic representation of the physical roadway characteristics of a highway as if it had no turns or curves.  Mileage is based on the centerline of the road as measured from the western or southern county line or other true beginning.  All routes on the Interstate, U. S. and State Route systems are shown on these diagrams.

All information contained in the SLD files is current as of January 1, 2009. 

SLD Sheets & Detail Sheets

There are two types of sheets.  "SLD sheets" generally depict from one to five miles of highway,  depending on the density of information. Also shown on the SLD sheets are crossing state routes, corporation lines, structures, and pavement and project information. (More information can be found in the Legend.)   "Detail sheets", are grade separated interchange drawings. (Please note, Detail sheets are not drawn to scale).

All SLD sheets and Detail sheets associated with a route are located in one file (by county). The Detail sheets that previously appeared on the back of the SLD sheets (in book form) now appear on subsequent pages in the SLD file. The number of SLD sheets and Detail sheets are displayed in each County table.

All the SLD files are in Adobe Acrobat (.PDF) format.  Each file should automatically open in the proper format and orientation for viewing or printing if Adobe Acrobat Reader is loaded.  (The required reader is free of charge and available through Adobe's website.)   

SLD File Names

The SLD file name is made up of a three character county code and route number. The route number consists of a two letter System prefix, (IR - Interstate Route, US - United States Route, SR - State Route), a four digit route number, and a single character route suffix. (Route suffixes are identified on the Legend.)

Interchange ID Numbers

All the SLD Detail sheets include an "Interchange ID Number".  This number is located under the sheet title. This unique identification corresponds to the interchange number and is fully integrated with the soon to be released Ramp Inventory System. All ramps for a given interchange will have this same ID number associated with it in the Ramp Inventory System


The Legend for SLD sheets and Detail sheets consists of three pages.  It includes Standard Surface Classifications, Standard Base Classifications, Route Identifications, Route Abbreviations and Suffixes, Special Symbology, etc.

Viewing  the SLD's

There are two ways to select a SLD for viewing.

Select Route by County: Each County Table contains a list of route numbers in that county. The table also includes the route length (in miles) for that county, the number of SLD sheets and the number of Detail sheets. The SLD file name is the link to the drawings. The tables are ordered by System precedence (IR, US, and SR), route number, and suffix.

One additional row is included at the top of each County Table which contains the combined route information for all the route types (IR, US, and SR) in each particular County. A ".pdf" file was also included to view the SLD and Detail sheets for the entire County.  This additional ".pdf" file was included so that users could easily view and / or print the SLD and Detail sheets for an entire County, with only one mouse click.

Straight Line Diagrams for the Ohio Turnpike (IR 0080K/IR0076K) are included on the appropriate county tables.  However, the mileage, number of sheets, and number of details sheets are not included in the county data and do not appear in the county SLD file.

Select by Route Number: A series of tables have been created for each type of route (Interstate, US, and State Route) within the State.

After clicking the type of route (and approximate Route Number for State Routes) from the small "popup" window, a new page will display in the right window with Route Numbers along the left margin.  The county abbreviations for each of the counties that the route runs through will also be displayed.  (This is the actual link to the SLD file.) Click on the county abbreviation.  The selected SLD will display in the right window.

A County Abbreviation table has been created for your reference.

Hints and Tips

A Hints and Tips page has been included to assist with use of this application. Information included on this page consists of suggested Printer Settings, Viewing Tips, and Manipulation of the "Pop Up" Windows.

Updates 2009

The Updates 2009 page includes information regarding changes that have been made to the Straight Line Diagrams (SLD) in the last calendar year (January 1, 2008 - December 31, 2008).  It is intended to provide quick, easy, simplified access to the SLD's that have been changed.  It replaces the paper transmittals that were sent out in the past.


The information provided on this Web site is an ODOT product and is not to be sold or otherwise distributed for profit. There are no expressed or implied warranties concerning the accuracy, completeness, reliability or usability of this information. Further, ODOT assumes no responsibility for any incorrect results or damage resulting from the use of this information. All users shall expressly hold ODOT harmless from any liability or loss due to any computer or software generated problems associated with these files. It is the sole responsibility of the user to keep all files current with those on the Web site. No technical support will be provided by ODOT.