We would like to thank the people behind the numerous sources (departments/ministries of transportation, hobbyist web sites, maps, road trip accounts, etc.) that have helped us in our research of the ever-changing routings of thousands of highways.

We use city coordinate data provided for free from the US Census 2000 Gazetteer and the World Gazeteer.

We have used many highway sign graphics created by either our collaborators or by the following helpful photographers and image designers. We would like to thank all of these individuals and organizations for granting us permission to use their work on this web site.

• David Backlin: Oklahoma turnpikes.
• James Lin: Connecticut Turnpike, New Brunswick highways.
• Zach Maillard: KS state highway shield.
• Dan Moraseski: Everett Turnpike.
• Alberta Ministry of Transportation: Alberta Highway Signs.
  Material taken from the Alberta Ministry of Transportation website is provided solely for the user’s information and, while thought to be accurate, is provided strictly “as is” and without warranty of any kind. The Crown, its agents, employees or contractors will not be liable to you for any damages, direct or indirect, or lost profits arising out of your use of this information.
• Nathaniel Porter: Great Britain Motorway Permanent font.
• Jake: Idaho highway shield.
• Kentucky Transportation Cabinet: Kentucky Parkway Shields.
• Various contributors to Wikipedia who have made their images public domain. (A specific list will be forthcoming.)