Now largely considered a predecessor to OpenTripPlanner, Graphserver  is perhaps the original open-source multimodal trip planning software. However, Graphserver, written in C and Python, is intended for software developers who are interested in algorithms research and transit analysis, not as a customer-facing multimodal trip planning or analysis solution. Graphserver core software development seems to have been inactive over the last year, although there is still activity on the Graphserver developers group. Transit agency staff interested in multimodal trip analysis who do not have a background in software development are directed to the OpenTripPlanner Analyst Extension.
- Brandon Martin-Anderson. "Graphserver." Accessed July 31, 2012 from http://graphserver.github.com/graphserver/