Arts and Environment Initiative
- http://ceed.allegheny.edu/A&EI/
- Part of the Center for Economic and Environmental Development at Allegheny College in Pennsylvania. Page shows recent projects including two involving the sculpting of road signs into art ("Read Between the Signs" and "Signs and Flowers").
MUTCD History
- http://tcd.tamu.edu/documents/MUTCD_History.htm
- Page by the Texas Transportation Institute illustrating the changes between each edition of the U.S. Manual on Uniform Traffic Control Devices. Also includes related articles.
Road Sign Math
- http://www.roadsignmath.com/
- Website that accepts submissions of photographs of sign assemblies whose numbers can be arranged to form a mathematical operation.