Northeastern US Highways - This mailing group is designed to discuss highway transportation in the Northeastern U.S. and the Northeast Corridor (Megalopolis), primarily from Pennsylvania north to the Canadian border.Roadgeek - Discussions of US and Canadian highways, including signage, numbering, and history. Basically a mailing list equivalent of misc.transport.road.
Yahoo! Groups: aussiehwys - Mailing list for those interested in Australian roads and highways, and associated infrastructure - e.g., signage, line marking, pavements, freeways, route numbering.
Southeastern US Roads - A group to discuss roads and transport in the southeast United States, from the Mason-Dixon line south to Florida and west to the Mississippi River.
Florida Roads - Covers the news, history, and other information related to roads in the state of Florida.
Canadian Roads - Mailing list for those interested in area highways.
Friends of Southern California's Highways - Advocates realistic, practical solutions to traffic congestion in Southern California.
Interstate Dreaming - A message board to discuss fictional Interstate highways.