| Studies
Urban
Trees and Traffic Safety
Across our nation, transportation policy
and practices regarding urban trees may affect the vitality
and livability of cities and towns. Professed reasons of driver
safety and property protection often justify trees being removed
or precluded in commercial streetscapes and along urban arterials.
This research is investigating the scientific basis of no-tree
transportation policy. Analysis of national crash data is
revealing the circumstances and attributes of tree collisions
in urban contexts. With better knowledge trees can be designed
into streetscapes more safely. (See bottom of page for Additional Publications)
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Dixon, K. K., & K. L. Wolf. 2007. Benefits and Risks of Urban Roadside Landscape: Finding a Livable, Balanced Response. Proceedings of the 3rd Urban Street Symposium (June 24-27, 2007). Washington D.C.: Transportation Research Board of the National Academies of Science. (1 M pdf) |
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Wolf, K. L. 2006 (December). Roadside Urban Trees: Balancing Safety and Community Values. Arborist News, 15, 6: 56-58. (148 K pdf) |
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Study Finds Transportation Policy Regarding Trees Outdated. The Forestry Source, August 2006, Vol. 11, No. 8, p. 13. (6.2 M pdf) |
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Wolf, K. L. 2006 (Spring). Urban Trees and Traffic Safety: Science to Practice. Woodnotes, 9, 1 (online) |
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Wolf, K. L. and N. J. Bratton. 2006. Urban Trees and Traffic Safety: Considering U.S. Roadside Policy and Crash Data. Arboriculture and Urban Forestry, 32, 4, 170-179. (180 K pdf) |
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Trees
in Urban Streetscapes: Research on Traffic Safety and
Crash Risk- Fact Sheet 18 (120 K pdf) |
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Bratton,
N. J. and K. L. Wolf. 2005. Trees and Roadside Safety
in U.S. Urban Settings, Paper 05-0946. Proceedings of
the 84th Annual Meeting of the Transportation Research
Board (January 9-13, 2005). Washington D.C.: Transportation
Research Board of the National Academies of Science. (104 K pdf) |
Large Transportation Structures - Human Perception
Urban transportation systems include large bridges, viaducts and freeway overpasses. The space beneath such structures has traditionally become a dead zone, neglected or used for bulk parking. Such spaces could be used more effectively, and include landscape improvements. The paper and presentation offer ideas, based on human perception studies, for how transportation infrastructure zones might be better used. The ideas were prepared in conjunction with design studies for replacement of the Seattle waterfront viaduct.
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Wolf, K. L. 2007. Transportation, Large Infrastructure, and Context in Urban Areas: A Review of Human-Scale Perception and Response, Paper 07-1842. Proceedings of the 86th Annual Meeting of the Transportation Research Board (January 21-25, 2007). Washington D.C.: Transportation Research Board of the National Academies of Science. (pdf
520 K) |
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PRESENTATION on 1-25-2007. Transportation, Large Infrastructure, and Context in Urban Areas: A Review of Human-Scale Perception and Response. 86th Annual Meeting of the Transportation Research Board (Washington D.C.) (1.1 M pdf) |
Trees and Parking Lots - Green Law for Urban Sustainability
Parking
lots occupy about 10 percent overall of the land in U.S. cities,
and can be as much as 20 to 30 percent of downtown core areas.
Large areas of asphalt and other impervious surfaces contribute
to environmental concerns such as heat island effects, reduced
air quality, and stormwater flows. This report summarizes
the municipal "green law" of numerous cities and
towns (with a focus on the SE United States), with regard
to landscaping and trees in parking lots. Multiple examples
of regulatory tools are provided, demonstrating how communities
can improve sustainability of urban areas.
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Wolf,
K. L. 2004. Trees, Parking and Green Law: Legal Tools
and Strategies for Sustainability. Woodnotes, 7, 2, (link)
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Trees,
Parking & Green Law: Legal Tools and Strategies for
Sustainability - Fact Sheet 15 (pdf
47 K) |
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Wolf,
K. L. 2004. Trees, Parking and Green Law: Strategies for
Sustainability. Stone Mountain, GA: Georgia Forestry Commission,
Urban and Community Forestry (pdf
2.7 M) |
Beyond
the White Line: Public Response to the Urban Freeway Roadside
This study explored public preferences and perceptions for
various landscape treatments of freeway roadsides. Using surveys,
drivers from the states of Washington, Minnesota, Michigan,
and Maryland were asked to rate scenes containing varied vegetation
content and arrangements. Drivers indicated highest preference
for roadsides having urban forest screening, and endorsed
agency management in support of roadside nature.
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Wolf, K. L. 2006. Assessing Public Response to the Freeway Roadside: Urban Forestry and Context Sensitive Solutions. Transportation Research Record: Journal of the Transportation Research Board, No. 1984, 102-111. (pdf
1.9 M) |
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Wolf, K. L. 2006. Assessing Public Response to the Freeway Roadside: Urban Forestry and Context Sensitive Solutions, Paper 06-1586. Proceedings of the 85th Annual Meeting of the Transportation Research Board (January 22-26, 2006). Washington D.C.: Transportation Research Board of the National Academies of Science. (pdf
1.1 M) |
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The
Freeway Roadside Environment: Testing Visual Quality
at the Road Edge - Fact Sheet 9 (pdf
132 K) |
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Wolf,
K. L. 2003. Freeway Roadside Management: The Urban Forest
Beyond The White Line. Special Issue on Social Aspects
of Urban Forestry. Journal of Arboriculture, 29, 3, 127-136.
(pdf
280 K) |
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Trees
in Business Districts: Testing Visual Quality at the Roadside
Edge. In Vistas, publication of the National Scenic Byways
Program, March 2001. |
Freeway
Roadside Landscape and Community Perceptions
Drivers
in the Pacific Northwest of the U.S. were asked to judge how
urban greening near freeways influenced their judgments of
roadside communities. The self-administered survey displayed
simulations of communities having different levels of green
space, near the freeway, and throughout a community. Higher
ratings of community appeal and greater willingness-to-pay
for goods were associated with community greening.
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Community
Image: Roadside Settings and Public Perceptions - Fact
Sheet 10 (pdf
148 K) |
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The
View from the Road: The Urban Forest and Our Freeways.
In TreeLink, newsletter of the Washington Department of
Natural Resources Community Forestry Program, No. 18,
Summer 2001. (pdf
1.1 M) |
Additional
Publications
Much of the research on trees and transportation safety was conducted on rural, high speed highways. Nonetheless, the findings of research of decades past are now broadly applied to urban and community transportation corridors by some transportation professionals. Yet traffic and roadside conditions in urban areas are quite different from rural counterparts. Below are publications that report on recent research and transportation planning that is specific to city settings.
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ITE (Institute of Transportation Engineers). 2010. Designing Walkable Urban Thoroughfares: A Context Sensitive Approach. Publication No. RP-036A. Washington D.C.: ITE, 215 pp. (11.5 M pdf). |
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Dumbaugh, E., & R. Rae. 2009. Safe Urban Form: Revisiting the Relationship Between Community Design and Traffic Safety. Journal of the American Planning Association, 75, 3, 309-329. (2.2 M pdf) |
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Macdonald, E., R. Sanders, & P. Supawanich. 2008 (November). The Effects of Transportation Corridors’ Roadside Design Features on User Behavior and Safety, and Their Contributions to Health, Environmental Quality, and Community Economic Vitality: A Literature Review (Final Report). University Of California Transportation Center, Berkeley CA, 211 pp. (1.2 M pdf). |
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Dumbaugh, E. 2005. Safe Streets, Livable Streets. Journal of the American Planning Association, 71, 3, 283-300. (5 M pdf) |
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Center for Transportation Research and Education. 2008. Clear Zone – A Synthesis of Practice and an Evaluation of the Benefits of Meeting the 10 ft Clear Zone Goal on Urban Streets. Ames, IA: Iowa State University, 140 pp. (full report 6.7 M pdf; executive summary 188 K pdf) |
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Macdonald, E. 2008. The Intersection of Trees and Safety . Landscape Architecture, 78, 2 (May): 54-63. (6.2 M pdf) |
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2008. NCHRP Report 612. Safe and Aesthetic Design of Urban Roadside Treatments. (link) |
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Naderi, J. R., B. S. Kweon, & P. Meghalel. February 2008. The Street Tree Effect and Driver Safety. ITE (Institute of Transportation Engineers) Journal, 78, 2: 69-73. (708 K pdf) |
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Topp, H.H. 1990. Traffic safety, usability and streetscape effects of new design principles for major urban roads. Transportation 16: 297-310. (800 K pdf). |
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2007. Getting Up to SPEED: A Conservationist's Guide to Wildlife and Highways. Defenders of Wildlife, Habitat and Highways Campaign. Washington D.C. (link) |
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Mok, J-H., H. C. Landphair and J. R. Naderi. 2006. Landscape Improvement Impacts on Roadside Safety in Texas. Landscape and Urban Planning, 78, 263-274. (pdf
660 K pdf) |
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Transportation
Studies: Social Science Approaches and Contributions
- Fact Sheet 7 (116 K pdf) |
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The
Calming Effect of Green: Roadside Landscape and Driver
Stress - Fact Sheet 8 (132 K pdf) |
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Zeigler, A. J. 1986. Guide to Management of Roadside Trees. Report FHWA-IP-86-17. Federal Highway Administration (FHWA). Washington D.C. (3.1 M pdf) |
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1987. Guidelines for Tree Planting and Maintenance on Urban Roads. Traffic Authority of New South Wales, AUS. 39 pp. (3.8 M pdf) |
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2002. Beautiful Roads: A Handbook of Road Architecture. Danish Road Directorate, Ministry of Transport, Denmark. (2.5 M pdf) |
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2003. Assessing
the Benefits of the Roadside Tree. Strategic Highway Safety
Plan - Trees - Appendix 13. National Cooperative Highway
Research Program. (link) |
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1999 (August). The
Nature of Driving: Roadsides Have Positive Effects and
Benefits. In Ex-Press, publication of the Washington State
Department of Transportation. |
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