Thursday, October 25, 2012

CycleUshare Research Paper Accepted at Major Transportation Conference

The first paper that we wrote related to the operation of this project has been accepted to the Transportation Research Board Annual Meeting in Washington DC in January. The paper received strong reviews and will hopefully make it into the Transportation Research Record Journal. Many of our users were a part of the study either passively (by using the system) or actively (by us interviewing them and discussing particular trips). A sneak preview of the paper:

North America’s first electric bicycle share: A year of experience 

by B.C. Langford, C. Cherry, T. Yoon, S. Worley, and D. Smith 


The integration of electric bicycles (e-bikes) with bicycle sharing can potentially increase the utility of bike sharing by reducing some barriers to bicycling and increasing the amount of prospective users. North America’s first e-bike sharing system (cycleUshare) at the University of Tennessee, Knoxville, offers a new, sustainable transportation option for students, faculty, and staff.  The cycleUshare system is a small pilot test with two stations to research the technology and user experiences. This paper presents an overview of the cycleUshare system and reports experiences from the first year of operation. With 93 enrolled users, cycleUshare provides a unique opportunity to study not only the system use, but also how individual users make trips with both regular and electric bicycles and the factors that influence those trips. The study finds that only 22% of users account for 81% of the trips. Factors of speed and convenience play major roles in participant’s decisions to use the system, and speed and comfort are the most influential factors in selection of an e-bike over a regular bicycle. Most of the reported trips are class related, although e-bikes are found to be used for a wide variety of trip purposes. Walking is the mode most displaced by the system indicating that e-bike sharing expands user mobility. Additionally user perceptions about bicycle types are explored. This model of electric bicycle sharing is found to be effective at attracting users to both regular and electric bicycles and is capable of expanding user mobility.

Still Moving Forward on New Software/Electronics

New Bike and Battery Rack Controller
Our systems are still running, but with some reliability problems. We have two problems (one at each station) that are both software related in different ways. We are very excited with the results of some of our field tests (you might notice the five positions on the right of the Ag Campus station are shut down for testing). The next step is tying it all together with a slick user interface, or a functional one at least. We have great programmers/electrical engineers from University of Tennessee and a recent grad from University of Washington working hard on getting a robust solution on the ground, which is quite exciting.
Field testing

Though delayed, our new system that will be released to the world with be modular, compact, efficient, customizable, and non-proprietary. 

Wednesday, August 22, 2012

Welcome to the new academic year

Welcome new students and staff and welcome back old users. We've gotten a lot of interest in participating in our system in the last couple of days with all the new students seeing our system. Our new software and electronics is still coming. We're going through some lab testing now to get it in good shape for public consumption. Unfortunately our big-time friends who are currently premier bikeshare company are having new software rollout delays too so we're not alone ( In the meantime, we'll get more aggressive about adding users into our system, though there will be a little bit of learning and relearning once we get our new software out. Also, since we're starting with a bunch of new users with our old software, everyone please pay careful attention to instructions. Our old (current) software can't handle user error. Our new (future) software will be a little more robust. Also make sure you watch the quick how-to video before you get to the station. 

Friday, June 29, 2012

Summertime for cycleUshare

It's been a while since the last post. The badly outdated "solar station not yet running" post was a little misleading. We're running, still dealing with a power-hog computer running down our solar capacity. We've developed an intermediate fix in the meantime. Now that we have some breathing room this summer, we're working on longer term fixes for the system.

This summer we have some big plans. First and foremost, we're pushing through with a true version 2.0 on the software (changing from Labview to C++), which is also going to include a big hardware redesign. Our prototypes work well enough to help us understand things we want to change and now we're pushing to get something that is a little more efficient and user friendly and hopefully more robust. We're redesigning all of our electronics to go along with it too, so that we'll have a scalable, reproducible solution. This should mean big changes for our system and our capability to expand beyond UT. We've got a bunch of places knocking on our door and now we'll have something to share.

Our second big change is, with the help of UT's communication office, we're updating our signage and logo's first you'll see some new signs out at the solar station. Some of our new logos are here. This went along with our website redesign that is hopefully a little more informative and up-to-date. Now that we're getting in a year's worth of data, look for some more research papers coming out of this system!

Friday, March 30, 2012

New Solar Powered E-Bike Station is Up (but not yet running)!

So, the new solar powered e-bike station is out on Ag Campus. This station is powered by ~1kW of solar arrays, run through an Outback Flexpower inverter and then to the batteries. An important part is that this station is off-grid so all of the operations and battery charging is done from solar! We pushed hard for about two weeks to get this finished, with most of station fabrication done at the Civil Engineering machine/fabrication shop and most of the electronics design and development done at the Biosystems Engineering Sensors and Controls Lab. We had a hardware/software problem when we hooked it all up that we're remedying now. We are up and should be running soon. Special thanks to students (Casey Langford, Taekwan Yoon, Ryan Overton, Levon Brassfield, Zane Pannell, and Kenric McKay) and staff (Stacy Worley, David Smith, Larry Roberts, and Ken Thomas) for the hard work, particularly near the end. We look forward to getting these bikes rolling soon. For now, check out the pictures of the fabrication at:

Tuesday, February 14, 2012

EV's (including e-bikes) need to pay attention to emission source

KNOXVILLE—Electric cars have been heralded as environmentally friendly, but findings from University of Tennessee, Knoxville, researchers show that electric cars in China have an overall impact on pollution that could be more harmful to health than gasoline vehicles.
Chris Cherry, assistant professor in civil and environmental engineering, and graduate student Shuguang Ji, analyzed the emissions and environmental health impacts of five vehicle technologies in 34 major Chinese cities, focusing on dangerous fine particles. What Cherry and his team found defies conventional logic: electric cars cause much more overall harmful particulate matter pollution than gasoline cars.

“An implicit assumption has been that air quality and health impacts are lower for electric vehicles than for conventional vehicles,” Cherry said. “Our findings challenge that by comparing what is emitted by vehicle use to what people are actually exposed to. Prior studies have only examined environmental impacts by comparing emission factors or greenhouse gas emissions.”
Particulate matter includes acids, organic chemicals, metals, and soil or dust particles. It is also generated through the combustion of fossil fuels.

For electric vehicles, combustion emissions occur where electricity is generated rather than where the vehicle is used. In China, 85 percent of electricity production is from fossil fuels, about 90 percent of that is from coal. The authors discovered that the power generated in China to operate electric vehicles emit fine particles at a much higher rate than gasoline vehicles. However, because the emissions related to the electric vehicles often come from power plants located away from population centers, people breathe in the emissions a lower rate than they do emissions from conventional vehicles.
Still, the rate isn’t low enough to level the playing field between the vehicles. In terms of air pollution impacts, electric cars are more harmful to public health per kilometer traveled in China than conventional vehicles.

 “The study emphasizes that electric vehicles are attractive if they are powered by a clean energy source,” Cherry said.”In China and elsewhere, it is important to focus on deploying electric vehicles in cities with cleaner electricity generation and focusing on improving emissions controls in higher polluting power sectors.”

The researchers estimated health impacts in China using overall emission data and emission rates from literature for five vehicle types—gasoline and diesel cars, diesel buses, e-bikes and e-cars—and then calculated the proportion of emissions inhaled by the population.

E-cars’ impact was lower than diesel cars but equal to diesel buses. E-bikes yielded the lowest environmental health impacts per passenger per kilometer.

“Our calculations show that an increase in electric bike usage improves air quality and environmental health by displacing the use of other more polluting modes of transportation,” Cherry said. “E-bikes, which are battery-powered, continue to be an environmentally friendly and efficient mode of transportation.”

The findings also highlight the importance of considering exposures and the proximity of emissions to people when evaluating environmental health impacts for electric vehicles. They also illuminate the distributional impact of moving pollution out of cities. For electric vehicles, about half of the urban emissions are inhaled by rural populations, who generally have lower incomes.
The findings are published in the journal “Environmental Science and Technology” here.

Cherry worked with Matthew Bechle and Julian Marshall from the University of Minnesota and Ye Wu from Tsinghua University in Beijing. The scientists conducted their study in China because of the popularity of e-bikes and e-cars and the country’s rapid growth. Electric vehicles in China outnumber conventional vehicles 2:1. E-bikes in China are the single largest adoption of alternative fuel vehicles in history, with over 100 million vehicles purchased in the past decade, more than all other countries combined.

This study is funded by the National Science Foundation’s Faculty Early Career Development (CAREER) award. The prestigious CAREER award supports junior faculty who exemplify the role of teacher-scholars through outstanding research, excellent education, and the integration of education and research within the context of the mission of their organizations. Cherry received his award in 2011. For more information, click here.