NCRoads.com: The Interchange Museum  
   Diagrams of unusual interchanges in North Carolina.
   http://www.ncroads.com/ic/icmuseum.htm

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

California Freeway Interchanges  
   Photos.
   http://members.cox.net/mkpl/interchange/interchange.html

Museum of Dumb Highway Design  
   Aerial photos of and commentary on various interchanges which the author finds unusual or substandard.
   http://www.weathergraphics.com/tim/dumbroad/

The Echelon Interchange  
   Professional paper on this part-at-grade, part-grade-separated intersection. [PDF]
   http://www.miller-consulting.com/echelon.pdf

Interchange of the Week  
   Detailed entries for locations in New York State, using official state aerial photography.
   http://www.empirestateroads.com/week/

Michigan Left Turn  
   Describes how this unusual intersection feature works, including history.
   http://www.michiganhighways.org/indepth/michigan_left.html

Unusual Interchanges  
   Diagrams and commentary of various ones in the East-Central U.S.
   http://www.lostagain.net/unint/

Highway Feature of the Week  
   Large archive of maps and descriptions of unusual or complicated facilities, primarily in the United States.
   http://www.gribblenation.com/hfotw/

WhereRoadsMeet  
   Contains aerial photographs and descriptions of unusual or complicated facilities in the United States.
   http://whereroadsmeet.8k.com/

Images of Britain - Spaghetti Junction  
   The M6 at the A38(M) in Birmingham.
   http://www.gayne.co.uk/iob/eng/wmids/ce00007.htm

Chris's UK Roads Directory - Bad Junctions  
   This page shows various badly designed interchanges.
   http://www.cbrd.co.uk/mistakes/badjunctions/

Continuous Flow Intersections  
   Engineering firm page illustrating the connections in this feature. Includes illustrations and a video demonstration.
   http://www.abmb.com/cfi.html