Information about the travel forecasting package, Quick Response System II
OD table estimation from traffic counts only makes sense if it is viewed as a method of statistical inference. Any other interpretation of OD table estimation causes splitting headaches. Now that we agree on this fact, we must also face the realization that there is a lot of junk masquerading as good technique. Short of …
It seems that empiricism in the absence of theory is the enemy of transferability. Physicists have postulated that the speed of light in a vacuum is a constant; no matter (not a pun) where or when it is measured, it is always the same. The speed of light is perfectly transferable. However, in travel forecasting …
The RADIUS models were originated by John Shaw, once of WisDOT and now working for the TOPS Lab at the University of Wisconsin—Madison. He envisioned using QRS II as a dynamic traffic assignment engine for a group of models for analyzing work zone traffic diversions. Part of the concept was synthetic OD table estimation from …
Estimating origin-destination (OD) tables from ground counts can be controversial. In many cases the number of variables of the estimation problem greatly exceeds the number of data points. This means that additional information must be gotten from somewhere, and the quality of that information is often suspect. QRS II contains many different methods for performing …
If you are reading this article you probably know something about equilibrium traffic assignment and how it is done in at least one travel forecasting package. Traditional methods of equilibrium traffic assignment, say Frank-Wolfe decomposition and MSA (method of successive averages) found in wide use around the world, converge to an equilibrium solution rather slowly. …
There is an idea floating around the transportation planning community that drivers are sensitive to the variability in travel time when choosing their routes. This idea suggests that drivers will tend to avoid short routes where the travel times are unpredictable and may instead choose longer routes where the travel times are consistent from day …