AARoads Roadtrips
Logs.

Multiplex Index
Gallery of shields along roads with more than one route number.

Roadgeeking
Louisiana, U.S. as well as Taiwan.

Interstate-Guide.com
Includes the Interstate Guide, the List of Interstate Business Routes, and the Interstate Shield Gallery. Extensive coverage.

Mike's Railroad Crossing Website
Covers the United States, Canada, the United Kingdom, and Australia. Also includes picture-taking guide, links, and FAQ.

Pictures of Highway Shields
Predominantly covers California, U.S. Also includes a discussion forum on roads.

Jonathan's Photographs
Culled from various trips around the world.

Mark Furqueron's Highway Page
Includes views mostly from the American West, predominantly California, as well as Asia and Europe. Includes pages on removed vintage signage.