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Research Shows Street Trees May Improve Traffic Safety

Posted: Aug 1, 2019

More trees and larger tree canopies in the "clear zone" near urban streets were associated with fewer injury/fatal crashes as well as fewer crashes overall in research conducted by MPC research at the University of Colorado Denver. That's contrary to 50 years of standard design practice which emphasized the expected safety benefit of roadside clear zones. The researchers found that while the number of street trees per mile is associated with improved safety in wealthier neighborhoods, a larger numbers of trees may be detrimental in low-income neighborhoods.

When assessing the safety impact of street trees in the clear zone, especially in urban areas, municipalities and transportation agencies need to be cognizant of context and the influence of street design changes on road user behaviors, the researchers noted. Changes to street design can have an impact on safety-related behavior such as travel speed and driver awareness. Beyond their economic and environmental benefits, street trees have long been a staple of good urban design and shaping more livable spaces.

Wesley Marshall, Ph.D.
University of Colorado Denver

The Unresolved Relationship Between Street Trees and Road Safety

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