Kendra K. Levine's blog

Mini-Bikes Safety Fact Sheet

Speeed Shriners

We have several obscure items in our collection. One we stumbled across today was the Consumer Product Safety Commision's 1978 Fact Sheet on Mini-Bikes. They cite that at the time of writing, 31,000 people a year require hospital treatment for mini-bike incidents. Their exmaple accident is described:


Safety tipes include:

  • Look for a mini-bike with large wheels. Typically, mini-bikes with small wheels are unstable.
  • The rider should be able to conveniently reach all controls without exerting himself.
  • After buying a bike, don't modify its design.

They also warn riders of impromper use and rider error:


The whole document, with several more tips on how to enjoy mini-bikes without a trip to the hospital, can be found here



Transportation mode recognition using GPS and accelerometer data


One of the big problems for smartphone travel diary apps is automatic mode detection. The split between walking and not is pretty easy, as is cycling, but what about separating cars from rail? Apps like Moves just dubs it "transport", but that doesn't help much with travel behavior research. A new paper in Transportarion Researc Part C examines using accelerometers and GPS to detect mode. Tao Feng and Harry J.P. Timmermans from Eindhoven University of Technology present their research in, "Transportation mode recognition using GPS and accelerometer data"

Potential advantages of global positioning systems (GPS) in collecting travel behavior data have been discussed in several publications and evidenced in many recent studies. Most applications depend on GPS information only. However, transportation mode detection that relies only on GPS information may be erroneous due to variance in device performance and settings, and the environment in which measurements are made. Accelerometers, being used mainly for identifying peoples’ physical activities, may offer new opportunities as these devices record data independent of exterior contexts. The purpose of this paper is therefore to examine the merits of employing accelerometer data in combination with GPS data in transportation mode identification. Three approaches (GPS data only, accelerometer data only and a combination of both accelerometer and GPS data) are examined. A Bayesian Belief Network model is used to infer transportation modes and activity episodes simultaneously. Results show that the use of accelerometer data can make a substantial contribution to successful imputation of transportation mode. The accelerometer only approach outperforms the GPS only approach in terms of the predictive accuracy. The approach which combines GPS and accelerometer data yields the best performance.

The full article can be found here

SafeTREC-UCTC Brown Bag Seminar: Transportation Policy in Oakland as It Is and as It Should Be

Latham square

This Friday, November 1 2013, the SafeTREC-UCTC Brown Bag Seminar features the City of Oakland's Senior Transportation Planner Jaime Parks. Parks will present, "Transportation Policy in Oakland as It Is and as It Should Be". 

Oakland has more BART stations than any other Bay Area jurisdiction, numerous mixed-use neighborhoods, and one of the highest bike-to-work mode shares in the country. Yet, the City has failed to fully take advantage of these natural advantages, partially due to the lack of a cohesive vision for the role transportation should play in the lives of Oaklanders. Oakland passed a Complete Streets Policy in 2013 that will allow the City to consider transportation decisions from a broader perspective. The presentation will share updates on several on-going complete streets initiatives, including analysis of crash trends Citywide, data management, CEQA reform, and experiments with green paint and temporary spaces. The presentation will also identify key knowledge gaps as suggested topics for future urban transportation research.

The seminar takes place from noon-1:00 PM SafeTREC 2nd Floor Conference Room, 2614 Dwight Way, Berkeley, CA
or via webcast

Friday Seminar: Decomposing connected vehicle dynamics: delay effects and nonlinearities

Interior: 2013 SRT Viper & SRT Viper GTS

Today's TRANSOC Friday seminar is about connected vehicles. University of Michigan's Gabor Orosz will present, "Decomposing connected vehicle dynamics: delay effects and nonlinearities".

Arising technologies related to vehicle-to-vehicle (V2V) and vehicle-to-infrastructure (V2I) communications can significantly improve the efficiency of connected vehicle systems. These allow cars to obtain detailed information about the motion of distant vehicles. Such information can be presented to the driver or incorporated in advanced vehicle control systems. In this talk I present some novel decomposition tools that allow us to untangle the infinite-dimensional dynamics of heterogeneous vehicular networks with V2V communication. These methods help us to understand the spatio-temporal complexity of large-scale multi-vehicle systems and redesign their dynamics by exploiting connectivity. Some similarities with flow oscillations on road networks equipped with V2I devices are also pointed out.

The seminar will take place at the usual time today, October 25, 2013 from 4:00-5:00 PM in 534 Davis. Cookie Hour will kick off in the library at 3:30 PM. 

Open Access Article: Spatial modeling of bicycle activity at signalized intersections

Biking at Grand/Halsted/Milwaukee (3 of 4)

This week is Open Access Week. What's Open Access? Here is a not very brief overview by Peter Suber. UC Berkeley also has an Open Access Initiative to help open up your research and data. 

In the spirit of Open Access Week, here's an interesting article from an open access journal - The Journal of Transport and Land Use. Go check it out and peruse the articles. No need to depend on your institution's sibscription because it's free to the public! (Thanks open access!)

In "Spatial modeling of bicycle activity at signalized intersections", Jillian Strauss and Luis F Miranda-Moreno look at the built-environment and cycling. 

This paper presents a methodology to investigate the link between bicycle activity and built environment, road and transit network characteristics, and bicycle facilities while also accounting for spatial autocorrelation between intersections. The methodology includes the normalization of manual cyclist counts to average seasonal daily volumes (ASDV), taking into account temporal variations and using hourly, daily, and monthly expansion factors obtained from automatic bicycle count data. To correct for weather conditions, two approaches were used. In the first approach, a relative weather ridership model was generated using the automatic bicycle count and weather data. In the second approach, weather variables were introduced directly into the model. For each approach, the effects of built environment, road and transit characteristics, and bicycle facilities on cyclist volumes were determined. It was found that employment, schools, metro stations, bus stops, parks, land mix, mean income, bicycle facility type (bicycle lanes and cycle tracks), length of bicycle facilities, average street length, and presence of parking entrances were associated with bicycle activity. From these, it was found that the main factors associated with bicycle activity were land-use mix, cycle track presence, and employment density. For instance, intersections with cycle tracks have on average 61 percent more cyclists than intersections without. An increase of 10 percent in land-use mix or employment density would cause an increase of 8 percent or 5.3 percent, respectively, in bicycle flows. The methods and results proposed in this research are helpful for planning bicycle facilities and analyzing cyclist safety. Limitations and future work are discussed at the end of this paper.

The full article can be found here

Special Friday Seminar: Marco Nie "From Pricing to Cap-and-Trade"


This week's TRANSOC Friday Seminar is at a special time - 11:00am - noon in 534 Davis. This week Northwestern University Associate Professor Yu (Marco) Nie will present on a cap-and-trade approach to congesiton management in "From Pricing to Cap-and-Trade: Analysis and Design of Quantity-based Approach to Congestion Management."

Traffic congestion continues to threaten economic prosperity and quality of life around the world. It is widely acknowledged that demand management is an indispensable ingredient in the recipe for solving the traffic congestion puzzle, and likely to be one of the more effective and cost-efficient if properly implemented. This research will explore a new and promising travel demand management strategy, inspired by various cap-and-trade schemes aiming to reduce greenhouse gas and air pollutant emissions. The cap-and-trade schemes considered in this research seek to couple direct travel demand restriction with a trading mechanism. Because such a scheme typically involves creating mobility credits and trading them in a market, it is also known as tradable credit scheme. In this talk we will examine a few key design issues involved in building such credit markets, including how to account for the effects of transaction cost and how to initially allocate credits, using various analytical models.

As noted above, the seminar is happening this Friday, October 25 2013, from 11:00am to noon in 534 Davis. We'll keep you posted about Cookie Hour. 

Great California Shake Out! Are you ready?

Oct. 18 1989 Cypruss Overpass Collapse

Today is the Great California Shake Out, a statewide earthquake drill.  Do you know what to do when the Big One comes? 

Ever since the 1989 earthquake and its effects on transportation infrastructure, such as the collapse of the Cypress Freeway (which of course was replaced) or the structural failure of a portion of the San Francisco-Oakland Bay Bridge, there has been considerable research on seismic safety and stability. Are aerial BART stations safe? What are the optimal risk-based maintenance procedures to earthquake safety for bridges and highways?

Of course the Los Angeles region has its own concerns about the Big One, such as the disruption of freight logistics for the mega-region. How will the region's highways be affected? There were lots of lessons learned from the 1994 Northridge earthquake, which help inform projections for future risks.

If you want more research about earthquakes and California transportation, of course turn to TRID. For today, think about what you'd do when the Big One hits and how you prepare for such an event. 

Stay safe. 

Friday Seminar: Dynamic Weather Routes

Southampton Airport

Seminar Time! This week's TRANSOC Friday Seminar is about smarter routing of flights to avoid severe weather. Dave McNally of NASA Ames Research Center, Aviation Systems Division will present, "Dynamic Weather Routes: The Search for Smarter Flight Routes"

Adverse weather is the leading cause of flight delay in the US National Airspace System. Airline flight dispatchers must file flight plans about an hour before push-back from the gate using their best available weather forecasts. FAA traffic managers assess the impact of weather on traffic flows, and, when necessary, implement standard reroutes for groups of flights. Given the uncertainty in weather, standardized reroutes may result in large buffers between flight routes and forecast weather. Weather changes as flights progress along planned routes, and because airline dispatchers and FAA traffic managers are busy, especially during weather events, they may miss workable opportunities for more efficient routes around weather. Dynamic Weather Routes (DWR) is a search engine that continuously and automatically analyzes in-flight aircraft in en route airspace and proposes simple route amendments for more efficient routes around convective weather while considering winds aloft, sector congestion, traffic conflicts, and active Special Use Airspace. NASA and American Airlines (AA) are conducting an operational trial of DWR at the AA System Operations Center in Fort Worth, Texas. A key result of the trial is that since airline operators are especially busy during weather events, it is more effective to let the automation identify and alert users to potentially high-value reroute options.

The seminar is Friday October 18, 2013 from 4:00-5:00 PM in 534 Davis. Cookie Hour happens at 3:30 in the library. See you there!

Ant colony routing for Freeways

ants all in it

Do we drive like ants? Researchers from TU Delft's Center for Systems and Control use an ant routing algorithm for freeways. "Ant Colony Routing algorithm for freeway networks" by Zhe Cong, Bart De Schutter and Robert Babuška, explore this topic. 

Dynamic traffic routing refers to the process of (re)directing vehicles at junctions in a traffic network according to the evolving traffic conditions. The traffic management center can determine desired routes for drivers in order to optimize the performance of the traffic network by dynamic traffic routing. However, a traffic network may have thousands of links and nodes, resulting in a large-scale and computationally complex non-linear, non-convex optimization problem. To solve this problem, Ant Colony Optimization (ACO) is chosen as the optimization method in this paper because of its powerful optimization heuristic for combinatorial optimization problems. ACO is implemented online to determine the control signal – i.e., the splitting rates at each node. However, using standard ACO for traffic routing is characterized by four main disadvantages: 1. traffic flows for different origins and destinations cannot be distinguished; 2. all ants may converge to one route, causing congestion; 3. constraints cannot be taken into account; and 4. neither can dynamic link costs. These problems are addressed by adopting a novel ACO algorithm with stench pheromone and with colored ants, called Ant Colony Routing (ACR). Using the stench pheromone, the ACR algorithm can distribute the vehicles over the traffic network with less or no traffic congestion, as well as reduce the number of vehicles near some sensitive zones, such as hospitals and schools. With colored ants, the traffic flows for multiple origins and destinations can be represented. The proposed approach is also implemented in a simulation-based case study in the Walcheren area, the Netherlands, illustrating the effectiveness of the approach.

You can find the full article here

San Francisco Travel Quality Study


A group of ITS Berkeley researchers need your help! The San Francisco Travel Quality Study is looking for participants right now. If you have an Android phone and use SF Muni, sign up!

What is the goal of the study? We want to understand how the quality of public transportation affects people’s choice of how to commute, and how Muni can best be improved to suit riders’ needs. This is an innovative study in which we want to get direct feedback from travelers. We are working with the SFMTA, so their voices will be heard! As a thank you, they receive a free Muni pass for a month!

Who can participate? Anybody who lives and works/goes to school in San Francisco; it doesn’t matter how they currently travel. Currently there is only an Android app available, but if resources permit, we might run an iPhone-based study early next year.

What does participation involve? The first round of the study runs from October 23 until December 7. Participants will be asked to install a survey app on their phones and use Muni on at least five days in November. They will then fill out the mobile mini-surveys (approx. 15 sec. each) for those days, plus three short online surveys (max. 10 min each) over the course of the six weeks of the study.

You can apply here.

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