I'm looking for open source tools for travel demand modelling (eg The four-step UTMS). Preferably in a GIS environment. That works well with Qgis, Grass and Postgis.
My question is not related to particular use case more research related.
My initial search had come up blank so I wanted confirmation.
Best Answer
The short answer is that there isn't one especially if you're looking for a TransCAD or Emme/2 alternative as there is no open source package that comes close to those.
The closest you can get are some micro modelling solutions like Transims or matsim that I find lacking of a lot of needed data, methodologies, tools, or network handling that are available in commercial software.
UrbanSim is an open source agent based modelling solution but as far as I recall it doesn't handle transportation networks.
On the other hand, I have developed 3 or 4 travel demand models based on QGIS. Although, I can't share the code with you, I can tell you what I did:
Capacity
-or- use best practices that are acceptable for the jurisdiction you're modeling.link ID, link name, speed, length, number of lanes, capacity per lane, total capacity, and directionality
U_turns allowed?, left_penalty, right penalty, average_Delay, accepted delay, green_cycle_time_per_leg
I compared my Hodgepodge model to TransCAD and it was pretty close; however, mine was 10 times as slow due to me doing it all in python and not in an organized way.
Let me know if you have more questions as I spend a lot of time working in this topic.
Also, it would help to know where you are and what's the scale you're looking for, municipal, versus state, versus national.