Thursday, November 08, 2007

Transportation Seminar and Cookie Time 9 November: A Macroscopic Approach to Urban Traffic

This week's talk, given by CEE PhD student Nikolas Geroliminis (CV in pdf format), approaches a description of vehicular movement in urban areas on a macroscopic scale. Geroliminis has formed his conclusions using both simulation and real data from metropolitan areas (here is a link to a 4-hour simulation by Geroliminis and Prof. Daganzo). Here is the abstract:
Various theories have been proposed to describe vehicular traffic movement in cities on an aggregate level. They fall short to create a macroscopic model with variable inputs and outputs that could describe a rush hour dynamically. My dissertation work shows that a Macroscopic Fundamental Diagram (MFD) relating production (the product of average flow and network length) and accumulation (the product of average density and network length) exists for neighborhoods of cities in the order of 5-10km2. It also demonstrates that conditional on accumulation large networks behave predictably and independently of their Origin-Destination tables. These results are based on analysis using simulation of large scale city networks and real data from urban metropolitan areas. The real experiment uses a combination of fixed detectors and floating vehicle probes as sensors. The analysis also reveals a fixed relation between the space-mean flows on the whole network and the trip completion rates, which dynamically measure accessibility. This work also demonstrates that the dynamics of the rush hour can be predicted quite accurately without the knowledge of disaggregated data. This MFD is applied to develop perimeter control strategies based on neighborhood accumulation and speeds and improve accessibility without the uncertainty inherent in today’s forecast-based approaches. The looking-for-parking phenomenon that extends the average trip length is also integrated in the dynamics of the rush hour

The seminar will be in 240 Bechtel at 4:00 and will be preceded by Cookie Time in the ITS Library (4th Floor McLaughlin) at 3:30. Please Note: Cookie Time will still be held regardless of other ITS closures for Veterans' Day

No comments: