Transportation models have used zonal geography and coarse representations of the transport network to represent the spatial environment for trip origins, destinations and routes. But the coarseness of the zonal geography and transport networks is inconsistent with the level of detail needed to represent walking and bicycling adequately. This also has implications for the representation of transit, which is so dependent on walk access at origin and destination of transit trips. This talk addresses recent work underway as part of projects funded by NSF and MTC, to develop an analytic and visualization capability at a level of detail of parcels and local streets. Preliminary development of an integrated database, model system, and visualization platform yields early insight into strategies to more fully represent pedestrians and bicyclists within land use and transportation models and planning.
The seminar will be on September 30th, from 4-5 pm in 406 Davis Hall. Cookie Hour preceeding, as usual, in the library at 3:30 pm. See you there!
The 2011 Urban Mobility Report builds on previous Urban Mobility Reports with an improved methodology and expanded coverage of the nation’s urban congestion problem and solutions. The links below provide information on long-term congestion trends, the most recent congestion comparisons and a description of many congestion improvement strategies. All of the statistics have been recalculated with the new method to provide a consistent picture of the congestion challenge. As with previous methodology improvements, readers, writers and analysts are cautioned against using congestion data from the 2010 Report. All of the measures, plus a few more, have been updated and included in this report.
You can download the full report here. They also include summary tables for quick analysis and you can access congestion data for your city and even download the data for all 101 cities. A wealth of information to use in your research. Good stuff!
This week's Friday Seminar is MIT's Marta C. Gonzalez presenting "Charactericing Urban Road Usage Patterns with a New Metric." The seminar will take place from 4-5 PM in 506 Davis Hall on 23 September.
Mobility data from half million anonymous mobile phone users are used for this presentation to study the road usage patterns in the Bay Area. Using this mobility data based on our modeling framework each trip’s route is predicted. Surprisingly, it is found that on average 60% of the vehicles passing through a road segment come from 1% of its drivers’ home locations, hinting to high predictability of the vehicle sources. To quantify the heterogeneous traffic contributions of the vehicle sources we use the Gini coefficient and find that a road segment’s Gini coefficient is poorly correlated with its betweenness, traffic volume and volume over capacity, suggesting that Gini coefficient is a new metric on top of the traditional measures, quantifying road usage patterns in the perspective of drivers’ demographic distribution. Finally based on the road usage patterns, we find an efficient strategy to mitigate traffic congestion through a tiny decrease of car usage rates in a few targeted neighborhoods.
Don't forget about Cookie Hour in the library at 3:30! See you then.
This afternoon, Spetember 21, there will be a special Wednesday Seminar. From 2-3 PM in 406 Davis Hall, Lin Zhang of Tsinghua University will present "Crowd-sourced Mobile Urban Sensing".
Wide area urban sensing is a topic of interest both within industry and academia, as well as a technique urgently needed by both city governments and urban residents. In today’s rapidly urbanizing world, the urban sensing system provides up-to-date, complete and detailed observations of the climate, environment, traffic, and population of a city, all information which can aid government officials in the decision-making process. The urban sensing system is also a frontier of Internet development, enabling cyber space to sense the ambient environments in which it is embedded. However, there are two major challenges to urban sensing: communication capacity and sensing capability.
This presentation will introduce a taxi-cab based mobile sensor system that was designed for wide-area urban sensing purposes. The presented system addresses both of the aforementioned challenges as well as considerations of economic and technical feasibility. The system crowd-sources the sensing tasks to a group of taxi cabs roaming the city, and uses the store-carry-and-forward mechanism to collect and send sensory data to the data center for processing. Compared to a static, dedicated sensor network, the system enjoys extremely low deployment costs with fairly strong coverage and performance. The presentation will also describe the details of the system design, including the wireless channel measurement, an energy efficient neighbor discovery method, a utility-based routing protocol for data delivery, and a compressive sensing field recovery algorithm that exploits the sparsity of the physical field in order to reduce the volume of the required sensing data. The presentation closes with a a discussion of future deployment plans and research directions for the system.
The impacts of recent changes in Federal light-vehicle fuel economy standards depend crucially on consumers’ response to new vehicles with higher fuel economy and higher prices. Previous studies have primarily relied on stated preference experiments since there was little independent variation in vehicle price, fuel economy, and performance. The recent introduction of hybrid-electric vehicles has provided some independent variation in these key vehicle attributes, so we use data from the 2009 NHTS data to estimate willingness to pay for light vehicle fuel economy. We also estimate the “rebound effect” of purchasing more fuel efficient vehicles. Finally we will comment on the impact of measurement errors and partial observability on previous studies.
The seminar will take place Friday, September 16, 2011 from 4-5 PM in 406 Davis Hall. Don't forget about Cookie Hour preceding it in the library at 3:30 PM. See you there!
"If the federal government and private investors are not going to provide funds, and California is broke, why would it take on an enormous new commitment?" asked Martin Wachs, a Rand Corp. transportation expert and former director of UC Berkeley's Institute of Transportation Studies.
In coming months, Gov. Jerry Brown will decide whether to issue the bonds to launch the project — at a time when the nation and state are attempting to control mounting public debt that has already damaged both their credit ratings.
The bullet train hinges on a huge investment of federal dollars when Washington is intent on cutting the nation's budget. Republicans who control the House of Representatives have already declared new rail construction their "lowest priority."