September 2011

Petaluma Going Yellow for Left Turns

left turn signal

Yesterday the Press Democrat reported on Petaluma replacing the "left on green" signals with flashing yellow lights

The city will replace all or some of the protected-permissive signals at 26 intersections throughout town, while allowing a few to remain as is.

Some will include a signal new to California and what may be a first for Sonoma County — the flashing yellow left-turn arrow.

Petaluma Boulevard North at Magnolia Avenue/Payran Street had a “higher than expected collision experience involving left-turning vehicles,” Zimmer said.

In all four directions, the protected-permissive signals will be replaced with protected left-turn phasing, meaning left-turn drivers will see a progression of green, yellow and red arrows.

Then, once the intersection is cleared, a flashing yellow arrow will light, alerting drivers that they may proceed with caution with a left turn when oncoming traffic is clear.

The 2009 MUTCD includes languange about flahsing yellows for left turns (4D.17-4D.20). The topic is also discussed in NCHRP Report 493: Evaluation of Traffic Signal Displays for Protected/Permissive Left-Turn Control. While Petaluma is the first city in California to implement this sort of signal, it has been catching on across the nation. Next year, two different research projects investigating the impacts of flashing yellows on protected left turns should be completed. One is Evaluation of Flashing Yellow Arrows (FYA) for Protected/Permissive Left Turn (PPLT) Control from Bradley University for the Illinois DOT. The other is Field Study of Driver Behavior at Flashing Yellow Arrow vs Green Ball Permitted Left-Turn Indications by CTS of the University of Minnesota for the ITS JPO of RITA

 (Hat tip to @thedotreport)

 

Raising Speed Limits: Impact on Safety?

Motorway Three

Today the state of Maine raised its speed limit from 65 to 75 mph. Across the Atlantic, today it was also announced that the British government wants to raise the speed limit to 80 mph. Proponents argue that increasing the speed limit will propmote economic growth through reducing congestion, which was touched upon in the TTI report "Speed Harmonization and Peak-period Shoulder Use to Manage Urban Freeway Congestion." Opponents are concerned about the implications on traffic safety. Purdue's Fred Mannering wrote about the relationship between safet and speed in his 2009 article, "An empirical analysis of driver perceptions of the relationship between speed limits and safety." In the report, "Long-Term Speed Compliance and Safety Impacts of Rational Speed Limits," researchers from University of Virginia and VTRC found that increased speed limits along with coordinated education and enforcement can be safe.

 

Friday Seminar - Paul Waddell on Pedestrian Scale in Transportation Models

pedestrian crossing

This week's TRANSOC Friday Seminar feature Paul Waddell from the Department of City & Regional Planning at Cal. He will be present, "Addressing the Challenge of Representing the Pedestrian Sclae in Transportation Models". 

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!

2011 Urban Mobility Report out now!

San Francisco - New Montgomery St.

The 2011 Urban Mobility Report has been released with week from the University Transportation Center for Mobility, a part of the Texas Transportation Insitute at Texas A&M. 

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!

Friday Seminar - Marta C. Gonzalez on Characterizing Urban Road Usage Patterns

Traffic I Missed

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.

Special Wednesday Seminar! Lin Zhang discusses Crowd-sourced Mobile Urban Sensing

taxis

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.

 

Celebrating Parkin(ing) Day 2011!

in

World's Park(ing) day in Sofia

Today is Park(ing) Day 2011! Started in 2005, this international event repurposes parking spaces to turn them into mini parks. Oakland is celebrating with 13 parklets, as well as San Jose, Walnut Creek, and Santa Rosa. Check out the map to find the parklet nearest you! The parklet featured above is from Sofia, Bulgaria. You can also follow along via the Park(ing) Day Flickr Pool and #parkingday on Twitter

Friday Seminar - David Brownstone on Fuel Economy Standards

green driving

Tomorrow's TRANSOC Friday Seminar is with David Brownstone of UC Irvine's Department of Economics. He'll present, "Consumer Response to Stricter Fuel Economy Standards."

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!

 

NYC announce their bikeshare program

 A bike share station (photo by Kate Hinds)

Today it was announced who New York City picked for their bikeshare program. The winner is.... Alta Bicycleshare! The same group who run the Capital Bikeshare in Washington DC, New Balance Hubway in Boston, Barclay's Cycle Hire in London, and Bixi in Montreal. The announcement included the launch of a new website for people to suggestion possible station locations. 

Transportation Nation was there to report on the launch, including some great pictures

CA on the line for bulk of high-speed rail costs?

CA High-Speed Rail Design Concept: Transbay Terminal, San Francisco

The Los Angeles times published an article yesterday about the murky future of federal funding for high-speed rail in the state.

 

"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."

This week it was also announced that the model and data used for ridership and revenue forecasts were sound. We'll have to wait and see how this progresses.