Kurumi's Field Guide to Interchanges
Descriptions and diagrams of many types.

NCRoads.com: The Interchange Museum
Diagrams of unusual interchanges in North Carolina.

An VRML rendering of the 15-91 interchange, Corona California.
A 4-level stack with one loop. Requires a VRML plugin to view.

SPUI's SPUI list
A list of single point urban interchanges, a fairly new type of interchange. Includes information on what a SPUI is.

Interchange Diagrams
Interchanges in Florida and New Jersey, U.S.

California Freeway Interchanges
Photos.

Jughandles
Outline of this at-grade feature found mostly in New Jersey, U.S.

Museum of Dumb Highway Design
Aerial photos of and commentary on various interchanges which the author finds unusual or substandard.

The Echelon Interchange
Professional paper on this part-at-grade, part-grade-separated intersection.

Interchange of the Week
Detailed entries for locations in New York State, using official state aerial photography.

Michigan Left Turn
Describes how this unusual intersection feature works, including history.

Unusual Interchanges
Diagrams and commentary of various ones in the East-Central U.S.

Highway Feature of the Week
Large archive of maps and descriptions of unusual or complicated facilities, primarily in the United States.

WhereRoadsMeet
Contains aerial photographs and descriptions of unusual or complicated facilities in the United States.

Interchange of the Week
Detailed entries for locations in the Ohio River Valley, using aerial photography.

Images of Britain - Spaghetti Junction
The M6 at the A38(M) in Birmingham.

Chris's UK Roads Directory - Bad Junctions
This page shows various badly designed interchanges.