But I thought I’d go back to what touched this whole business off — the politically-motivated shutdown of the George Washington Bridge. Christie claimed that the shutdown was required for a traffic study, and tried to make a lame joke about being the person who personally set out the orange traffic cones to close the lanes for the study.
There’s one small problem with this tale — per traffic experts such as Washington State Department of Transportation traffic analyst Doug McClanahan, there’s almost never any need anymore to shut down traffic lanes to do traffic studies:
To do their traffic studies without getting in the way of drivers, McClanahan and his colleagues turn to traffic microsimulation software, such as Corsim and VISSIM. Corsim is a Windows-based traffic simulation and analysis program developed by the Center for Microcomputers in Transportation (McTrans), which was established by the Federal Highway Administration. VISSIM, also a Windows application, was developed by PTV Planung Transport Verkehr AG in Karlsruhe, Germany. (The acronym is for German words that translate as “Traffic in cities – simulation model.”)
Video cameras and human counters are used to gather data in the initial phases of a traffic study, and this data gathering can easily be done without disrupting traffic at all, according to McClanahan. The data is then plugged into computer models which run simulations.
Image courtesy UC Davis.