Analysis of the Benefits of Green Streets

Analysis of the Benefits of Green Streets

Abstract: 

Green streets offer many potential benefits that include improving water quality, absorbing carbon (sequestration), and reducing urban heat island effects. This report summarizes: (1) the research team’s analysis of 14 tools calculating green streets benefits; and (2) the results of applying the most promising calculators to a select group of green streets case studies. The researchers are affiliated with the Mineta Transportation Institute, which serves the California Department of Transportation (“Caltrans”). The report presents the results of the case study analyses, with an emphasis on carbon sequestration benefits and improvements to pedestrian levels of service (PLOS).

Trees absorb carbon dioxide and other pollutants from the air, reducing the costs of future climate change mitigations and medical care. Key findings obtained using i-Tree Design suggest that the monetary value (CO2 and air quality) of planting street trees is small but significant, with total estimated benefits from street trees on seven case study sites ranging from a low of $1,466 to a high of $9,420 over a 20-year period. On a per tree basis, the lowest benefits come from site 3A (Cherry Avenue in San Jose) with $10 per tree, and the highest come from site 1A (San Pablo Avenue in El Cerrito) at $175 per tree.

While the Landis PLOS method accounts for the benefits of short street tree spacings (i.e., a high number of trees) and of having a continuous biostrip or planter strip serving as a pedestrian buffer, the method does not appear to be sensitive to tree spacings, though it is very sensitive to buffers. Therefore, the importance of having a biostrip or planter strip buffer between the sidewalk and street traffic is also reflected in the PLOS findings in this study.

While the measurable benefits of a handful of street trees may seem small, this study suggests that using i-Tree Design to add together the trees planted by local and state agencies has the potential to provide a compelling picture of the carbon sequestration benefits across California. Similarly, the use of Highway Capacity Manual (HCM)-based pedestrian level of service methods by transportation professionals can bring significant gains in the appreciation of green streets’ benefits.

Authors: 

CHRISTOPHER FERRELL, PHD
Dr. Ferrell began his career in 1995 as a planner for the Metropolitan Transportation Commission (MTC). He completed his doctoral studies in City and Regional Planning at the University of California at Berkeley in 2005 and worked as a consultant with Dowling Associates, Inc. for 10 years before leaving to help form CFA Consultants in 2010. He is currently a principal and executive director of Transportation Choices for Sustainable Communities Research and Policy Institute. He has been the principal investigator for six research projects for the Mineta Transportation Institute, where he has been a Research Associate since 2005. His research focuses on the relationships between transportation and land use, livability, travel behavior, transportation policy and planning-related institutional structures. His research experience includes the study of multimodal transit and freeway corridors, the best practices for building successful transit-oriented development, the effects of transit-oriented development on surrounding property values, the effects of neighborhood crimes on transportation mode choice, and a set of methods, metrics and strategies for evaluating transit corridor livability. As a practitioner, he has planned mixed-use, infill and transit- oriented development projects, analyzed the impacts of specific and general plans, planned and implemented intelligent transportation systems, and developed bicycle and pedestrian plans. He has taught several quantitative methods classes in the San Jose State University Urban Planning Department and a course in transportation and land use in the City and Regional Planning Department at the University of California at Berkeley.

JOHN M. EELLS, MCP
John Eells is a transportation planner with 42 years of experience preparing comprehensive transportation plans and developing sustainable transportation projects at the local and regional level. John’s experience includes 2 years in the Legislative Analyst Office in the California State Legislature, 5 years with the California Department of Transportation (Caltrans), 7 years as the Transportation Planning Coordinator for Marin County and 28 years as a consultant.

He holds a bachelor’s degree in Architecture and a master’s degree in City Planning from the University of California at Berkeley. John has assisted in the preparation of Regional Transportation Plans for Sacramento and Lake Tahoe and reviewed Regional Transportation Plans throughout California for conformance with State greenhouse gas reduction requirements for the California Attorney General’s Office. He participated in a joint effort by Caltrans and the California Council on Science and Technology to develop a proposal for a new California Center for Transportation Innovation to coordinate transportation research activities in California. John has also managed major multi-modal transportation studies, evaluated the feasibility of proposal ferry services, and worked on the implementation of several rail transit projects including the Sacramento Light Rail project, the ACE Commuter Rail Service from Stockton to San Jose, the SMART Commuter Rail Service from Cloverdale to Larkspur, proposed AMTRAK services from Oakland to Reno, and the proposed high speed Maglev Service from Los Angeles to Las Vegas.

RICHARD W. LEE, PHD
Dr. Richard Lee is an adjunct lecturer in the Urban and Regional Planning Department at San José State University and a course instructor for UC Berkeley’s Transportation Tech Transfer program. He has been a research associate with the Mineta Transportation Institute (MTI) for over 20 years. For MTI, Richard has led major research studies of general plans and sustainability, airport planning, and sustainability indicators for transportation. From 1995 through 2002 he was a full time academic, teaching transportation planning and leading research projects at Massey University, New Zealand, UCLA, and Cal Poly San Luis Obispo. Richard is also Director of Innovation and Sustainability at VRPA Technologies, Inc., a California-based consulting firm, as well as a Principal at transportchoice.org, a non- profit research and educational institute. Dr. Lee’s 35 years of academic and consulting experience includes management of regional transportation plans, general plan studies, high-speed rail. He has planned transit improvements for systems ranging from BART to single route systems in the San Joaquin Valley and covering all transit modes. He recently led both a long-range transit plan for the Fresno region and a short-term route restructuring study for the City of Fresno’s transit system to incorporate bus rapid transit. Dr. Lee holds master’s degrees in Civil Engineering (1984) and City and Regional Planning (1985) and a Ph.D. in City and Regional Planning (1995), all from the University of California at Berkeley.

REYHANE HOSSEINZADE, MUP
Reyhane Hosseinzade is a transit service planner at Valley Transportation Authority (VTA). Her current responsibilities at VTA include passenger facilities planning and design, development and construction projects review, and bus stop improvements. Reyhane has been a research assistant at MTI for over a year. She has experience working on active transportation planning projects including an MTI research project analyzing the bike riders and pedestrian’s safety aspects of routes to school. She has over nine years of experience in urban design, data analysis and GIS. She obtained her master’s degree in Urban and Regional Planning from San Jose State University. Reyhane also holds another master’s degree in Urban Design. She is currently a PhD student in Transportation, Technology and Policy program at the University of California, Davis.

Published: 

September 2020

Keywords: 

Pollution control
Air quality management
Water quality management
Walkability
Complete streets
Green streets