Designing and maintaining roadside vegetation in highly developed urban settings is increasingly challenging for state transportation agencies (DOTs). In many cases, park-like and ornamental plantings installed on urban roadsides when the freeway was originally constructed have proven unsustainable for DOTs. The inability to adequately access and maintain these areas has resulted in failure of planted vegetation, loss of investment, and public criticism of state transportations agencies.
Factors contributing to the challenges of designing and maintaining urban freeway roadsides include:
• Constant high traffic volumes create safety risks for maintenance workers, difficult site access, and extensive traffic control requirements.
• Ongoing expensive investment in added labor, equipment, and materials, particularly where permanent irrigation and perpetual mowing is required.
• Illegal camping by transient populations.
• Noxious and invasive vegetation problems.
The objective of this synthesis is to document practices by DOTs to address problems related to urban freeway roadsides. The synthesis will focus on design and maintenance of vegetation along high visibility urban freeways with limited pedestrian access, such as wider medians, interchanges, roundabouts, and overpasses.
Information to be documented includes, but is not limited to, the following:
• Goals for vegetation management (e.g., safety, aesthetics, tourism, sustainability);
• Roadside design and installation specifications;
• Roadside integrated vegetation management plans for urban roadsides;
• Qualification, training, and certification of designers, construction inspectors, and maintenance staff relative to the vegetation aspects of an urban freeway roadside project;
• Strategies and policies related to appropriate plant selection and placement;
• Other challenges encountered by DOTs with vegetation management along urban freeway roadsides;
• Maintenance agreements between DOTs and local entities;
• Effective vegetation deterrents to illegal camping and other unauthorized uses;
• Work zone safety (e.g., access, personal safety, biohazards, wildlife); and
• Lessons learned
Information will be gathered through literature review, survey of all state DOT agencies, and follow up interviews with a least four agencies for case examples. The survey will be directed to state maintenance engineers. Surveys require an 80% response rate. The synthesis will identify gaps in knowledge and research that could address those gaps.
Jo Allen Gause
First Panel: November 16, 2017, Washington, DC
Teleconference with Consultant: December 11, 2017, 10:00 a.m., EST
Second Panel: August 14, 2018, Washington, DC
David W. Crawley, Manager-Landscape Architecture & Design Group
Amanda A. Fowler, Texas DOT
Valerie Friedmann, Auburn University
Scott Lucas, Ohio Department of Transportation
Kevin Schot, Florida DOT
Raymond Willard, Washington State DOT
Morgan Kessler, Federal Highway Administration
Carolyn Nelson, Federal Highway Administration
Nancy M. Whiting, Transportation Research Board