San Diego Commercial Vehicle Survey and Model
The San Diego Association of Governments (SANDAG), wanted to improve the treatment of commercial vehicles within their highly advanced and modern model framework. HBA Specto was commissioned to lead a combined survey and model project. The survey phase was an establishment-based survey of work-related travel including nonauto modes; HBA Specto designed the survey and managed the survey data collection project, which collected over 3,500 individual surveys from over 350 firms.
For the model, due to the relatively small survey sample size, the models used in the Calgary Commercial Vehicle Model were used as a starting point. A nested choice model connects tour generation, tour start time, and vehicle purpose in a consistent structure. The time of day components were completely redeveloped to match the time periods used in the SANDAG model framework.
The industries were increased to seven different industry categories representing the difference between the office and service sectors in San Diego. A toll choice model was added, with commercial vehicles explicitly choosing whether to travel on toll routes based on their relative benefits.
These models were calibrated to local data in all dimensions including tour generation, vehicle type, trips per tour and trip length.
The resulting model validated well against all available counts.
The model software operates using a combined Python/Java software environment and was incorporated with the other SANDAG models operating in the TransCAD software package.
