Control of vegetation along roadsides is required for fire prevention, adequate sight distance, facility inspection needs, reduction of invasive and nuisance weeds, roadside aesthetics, and protection of roadside appurtenances. Roadside vegetation can be controlled using herbicides, mowers, and other equipment or by long-term vegetation controls.
Long-term vegetation controls decrease the need for recurring chemical and mechanical vegetation control, thus reducing recurring maintenance costs, highway worker exposure to traffic, impacts to the environment and cultural resources, and maintenance-related delays to the traveling public. Additional advantages include maintaining the integrity of highway surfaces by controlling erosion and damage to the pavement structure from encroaching roots and water intrusion. However, these vegetation controls vary in their effectiveness, longevity, initial construction costs, maintenance requirements, and aesthetic values. Some treatments may also affect the safety performance of highway appurtenances, such as guardrails, cable barriers, and signs. For example, continuous asphalt or concrete may potentially result in pocketing or rupture of strong-post guardrails.
The objective of this research is to produce up-to-date guidance for transportation agencies for selecting appropriate vegetation controls that will be effective in preventing or significantly retarding the growth of unwanted vegetation around roadside appurtenances and along roadsides. The guidance will identify controls appropriate for new construction and for existing facilities. In addition, the guidance will describe how to select effective long-term vegetation controls that also address traveler and highway worker safety and costs of construction and maintenance, as well as minimize adverse environmental impacts.
STATUS: Research is complete. Final report and downloadable tool to select vegetation management strategies is available here: DOI: 10.17226/26876