UH Manoa Department of Urban and Regional Planning Research Highlight: Spring 2019

This article highlights a recently published study that Peter Flachsbart, a UH Manoa DURP faculty member, co-authored that describes findings of a long-term study on passenger exposure to carbon monoxide inside a vehicle traveling on a California highway. The article also highlights research developed by Andy Yamaguchi (DURP '18) that assesses the benefits and barriers to condo-based car-sharing in Kakaako. Andy's research was developed as part of his area of concentration studies in DURP's Master of Urban and Regional Planning program. 

Peter Flachsbart

Peter Flachsbart is an associate professor with UH Mā=noa’s Department of Urban and Regional Planning. He has been a faculty member of the department since 1980 and received his doctorate in urban planning from Northwestern University. Peter has held professional appointments at Stanford University; California State University, Dominguez Hills; and the University of Southern California. He currently serves as the APA Hawai‘i Chapter’s Professional Development Officer and has helped many of our colleagues prepare for the AICP certification exam. He was the recipient of the APA Chapter President’s Council Leadership Award in 2013.

Trends in passenger exposure to carbon monoxide inside a vehicle on an arterial highway of the San Francisco Peninsula over 30 years: A longitudinal study

Peter Flachsbart and Wayne Ott


This paper describes a long-term trend study of passenger exposure to carbon monoxide (CO) inside a vehicle traveling on an arterial highway in northern California. CO exposure was measured during four field surveys on State Route #82 (El Camino Real) on the San Francisco Peninsula in 1980–1981, 1991–1992, 2001–2002, and 2010–2011. Each field survey took at least 12 months. Fifty trips from each survey—for a total of 200 trips—were matched by date, day of the week, and starting time of the day to facilitate comparisons over three decades. The mean net CO concentration of each trip was obtained by subtracting the background CO level from the average CO concentration for the entire trip. The mean net CO concentration (0.5 ppm) for 2010–2011 was only 5.2% of that (9.7 ppm) for 1980–1981. For the 50 trips, the average travel time for the 1980–1981 period (39.6 min) was only 8.3% higher than during the 2010–2011 period (36.3 min). The estimated round-trip distance on the highway was held constant at 11.8 miles. The reduction in the mean net CO concentration was attributed to more stringent CO emission standards on new vehicles sold in California since 1980. The state’s cold-temperature CO standard implemented in 1996 appeared to reduce high CO concentrations that were observed during the late fall and winter of 1980–1981. In addition, the observed standard deviation in concentration fell from 3.1 ppm in 1980–1981 to 0.2 ppm in 2010–2011, and the range of the 50 mean net CO concentrations narrowed from 14.9 ppm in 1980–1981 to 1.1 ppm in 2010–2011, but the relative variability, as indicated by the geometric standard deviation, remained the same. These results have important scientific implications for regulatory policies designed to control air pollution from motor vehicles.

Implications: Many developing countries launched or expanded their mobile source emission control programs in the 1990s, yet many of them do not have adequate inspection and maintenance (I/M) programs. The El Camino Real study shows the long-term public health benefits of more stringent motor vehicle emission standards for carbon monoxide (CO) on new cars and of an I/M program (Smog Check) on the existing fleet in California. The study provides a protocol for conducting standardized field surveys of in-vehicle exposure on a periodic basis. Such surveys would enable developing countries to assess the progress of their mobile source emission control programs.

Please contact Peter at flachsba@hawaii.edu for a copy of his study.

Andy Yamaguchi

Andy Yamaguchi is a 2018 master's degree graduate of the University of Hawaii at Manoa Department of Urban and Regional Planning, where his focus was on transportation policy. He is a planner with the Development Plans and Zone Change Branch of the Honolulu Department of Planning and Permitting. Prior to his mid-life return to school, Andy was a reporter and editor for 35 years at the Spokane (Wash.) Spokesman-Review, Honolulu Advertiser, and Honolulu Star-Advertiser, where his beats included state and city government and land use planning.

Condo-Based Car-Sharing: Assessing its Potential Role in the TOD Toolkit


An oversupply of parking has frustrated cities’ efforts to realize the transportation and land use goals of transit-oriented development (TOD). Too much parking induces driving and takes up valuable urban space. On-site residential car-sharing could be an instrument for government to encourage or mandate less parking in new development, as one car-sharing vehicle can do the work of several personal vehicles. This paper sought to assess benefits and barriers to condo-based car-sharing through the perspectives of four stakeholder groups: government, residents, developers and car-sharing companies. I interviewed stakeholders, reviewed the academic literature and surveyed Kakaako residents. I concluded that condo-based car-sharing would be effective only if deployed as part of a larger, comprehensive transportation- and parking-demand management program. I recommend policies such as requiring car-sharing in new, large multifamily residential buildings; capping the amount of parking in new multifamily buildings; unbundling parking from the sale or lease of apartments; requiring car-sharing parking to be visible and accessible; and other steps. This issue is timely as TOD projects rise in Kakaako and Ala Moana, construction advances on Oahu’s rail transit system, and car-sharing companies deploy increasing numbers of vehicles in Honolulu.

Please contact Andy at andyyamaguchi@hotmail.com or the UH Manoa Department of Urban and Regional Planning at idurp@hawaii.edu for a copy of this study.