Seven quick things I learned about bicycling nationally

By Jennifer Dill, TREC director.

I recently completed a national poll of people living in urban areas in conjunction with the National Association of Realtors® on Community and Transportation Preferences. The overall results are posted here. The survey included 3,000 adults living in the 50 largest urban areas in the U.S. (That includes suburban areas, as well as denser urban cores.) Here are some highlights related to bicycling.

1.    Less than one in five people have biked in the past month.

Overall, 72% of the adults surveyed said they were physically able and know how to ride a bike. Of those, 25% had ridden in the past month. (The survey was conducted in mid-May, so weather was reasonable.) That means only about 18% of adults in these urban areas biked recently. Most of the people who had biked, rode only for exercise (60%, or 15% of those who are able to bike), while the others (40%, or 10% of those who are able to bike) made at least some bike trips for transportation, such as to work, school, shopping, etc.
Note: From here on I will be focusing only on those people who are physically able and know how to ride a bike.

Do person trip rates vary across contexts?

By Kristina M. Currans

In August 2014, the Institute of Transportation Engineers released the 3rd edition of the Trip Generation Handbook, a 352-page text that has traditionally, until only recently, provided guidance on estimating vehicle trips generated from new development. Among other updates, this new edition includes new chapters summarizing the most recent research and methods developed allowing users to account for people (not just vehicles) in trip generation estimation practices. This industry’s transition to estimating and understanding the “people” traveling to development has been in high demand from communities looking to accommodate multimodal travel, but there still remain a number of limitations in the guidelines presented.

What do students in the iconic Traffic and Transportation course value most?

By Nathan McNeil

I’ve been working through some survey data as part of a case study of the Portland Traffic and Transportation Course (, and thought I would share a few interesting differences that I’ve come across between course participants who commute via different modes.

As a bit of background, the course is a 10 week class jointly offered by Portland State University and the City of Portland that is open to the general public (not just PSU students) and provides a background in “local traffic and transportation issues, transportation options, and how to get things done in your neighborhood.” Being open to the public and providing a considerable depth of transportation-focused information, from history to engineering, the class is a relatively unique civic offering. The case study and an accompanying curriculum for other cities to implement a similar transportation-focused course will be completed in the coming months (more details are available at

Are e-bikes faster than conventional bicycles?

Over the last couple years, electric bicycles (e-bikes) have been gaining momentum. E-bikes may play an important role in addressing cities’ transportation and public health problems by getting more people out of cars and onto bicycles. But as the number of users increase, so too will potential conflicts (actual or perceived) with other road users, causing policy questions to arise.

The current state of e-bikes regulation varies dramatically across state and local jurisdictions, causing confusion. The confusion stems from the wide variety of devices and technologies on the market, perceived overlap of legal entities’ jurisdiction over the device, outdated or absent laws and regulations, and inconsistency of terms used to describe e-bikes. This confusion creates uncertainty for manufacturers and dealers and makes riders wary of embracing e-bikes.

Do perceptions match reality when riding in a green lane?

By Jennifer Dill, Ph.D.
Professor, Urban Studies & Planning 
Director, TREC

This week I’m at the International Travel Survey Conference in Australia. The conference happens every three years, attracting over 100 geeky people who spend time thinking about things like stated preference experiments, smartphone data collection, combining sampling frames, and respondent burden. I presented some work from our five city Green Lanes project, comparing our survey data with “objective” measures, such as videos and traffic counts. The focus was on intersections, where the protected lane is no longer separated from motor vehicles. An example of one design used in Portland, OR is shown in the adjacent figure.


Early insights into peer-to-peer carsharing

By Jennifer Dill, Ph.D.
Professor, Urban Studies & Planning
Director, TREC

The sharing economy is getting a lot of attention these days, both good and bad, from policymakers to Portlandia. We’ve been studying one type of sharing—peer-to-peer (P2P) carsharing. Carsharing allows individuals who want access to a car to rent one rather than having to deal with the cost, hassle or commitment of ownership.  Traditional carsharing companies, such as Zipcar, provide a fleet of vehicles located near residential or employment concentrations that members can rent. P2P carsharing is similar, but involves one private citizen renting a car from another, usually facilitated by a company that manages reservations and payment and provides additional insurance.

Our research has two main objectives. First, we’re looking at whether P2P carsharing will reduce vehicle miles travelled (VMT) and car ownership. Research on traditional carsharing shows that it can reduce driving by affecting the behavior of the renter, by making costs more explicit and by reducing ownership. With P2P carsharing, we’re also looking at the car owners’ behavior. The hypothesis is that owners might leave their car at home more often so that it is available for rental, thus earning more income. The second objective is to see whether P2P carsharing expands mobility options in economically and socially diverse areas. This might happen because traditional commercial carsharing companies typically locate vehicles in economically strong, relatively dense areas, whereas P2P vehicles could be anywhere people own cars they are willing to share. And, vehicles may also be more affordably priced.

Our three-year research project, funded by the Federal Highway Administration, is nearing the end of the data collection phase. We recruited 334 car owners and 465 car renters to participate in the study. They all live in the city of Portland and are participating in Getaround’s P2P carsharing service. We’re collecting pre, interim, and post surveys, as well as using GPS data from the vehicles to measure changes in VMT. We’re still processing the millions of GPS data points, and finishing up surveys from several participants, but we do have some early findings to share.

Welcome to the TREC Blog

Jennifer Dill, Ph.D.
Professor, Urban Studies & Planning
Director, TREC

University transportation research often follows a typical pattern. You write a proposal and it gets funded. You engage some bright graduate students and hopefully community partners. Collect data. Analyze data. Draw conclusions. Most projects take at least a year, often 2-3 years. It takes longer for the results to get out in a peer-review journal or final report. That can sometimes be frustrating.

The purpose of this blog is to allow our TREC researchers to present their research in a different forum. This can allow us to share early results or findings that are interesting, but may not make it into the journal article. We can also reflect on and discuss how our work relates to current events or public debates, without the constraints of academic journals. We’ll cover a wide range of topics that reflects the breadth of what we’re doing at Portland State. You’ll hear from faculty, researchers, and graduate students. We hope you enjoy it.