Roadside Vegetation Management in California

The State of California’s Department of Transportation (Caltrans) is California’s equivalent to the Department of Main Roads in Queensland or the Roads and Traffic Authority in NSW.

The Project Representatives met with five of the Caltrans team and they were very open in sharing their challenges as well as their successes. It was a terrific opportunity and we learnt a heap from the day, as well as made some great contacts who have offered to collaborate with us.

The purpose of the visit was for Project Representatives to review the on-ground success of the Caltrans Roadside Management Toolbox, a web based decision making tool developed to improve the safety and maintainability of transportation infrastructure.

The Roadside Management Toolbox provides design techniques and treatments that improve traveller and worker safety, protect the highway infrastructure and improve transportation system reliability by reducing the need for recurrent vegetation maintenance activities.

The California Department of Transportation manages approximately 15,000 miles of highway and 230,000 acres of right-of-way throughout California. The management, maintenance and control of vegetation on the roadsides have become increasingly difficult as the miles of roadway and acres of roadside have increased while maintenance resources have been reduced.

Historic methods of vegetation control (manual, mechanical and chemical) have been sharply curtailed due to local development, increased traffic volumes, public concerns and other economic and environmental issues.

Following a 1992 Environmental Impact Report on Caltrans vegetation control practices, the Department adopted a formal Integrated Vegetation Management (IVM) program for its roadsides. A major component of this program is permanent vegetation control techniques that reduce the need for ongoing vegetation management.

Since the adoption of IVM, District and Headquarters functional areas have completed research and field trials of a wide variety of permanent vegetation control approaches. The toolbox includes treatments composed of materials familiar to traditional highway construction contractors (such as asphalt and concrete, concrete and road base) as well as less conventional materials or products (such as polyurea coatings, rubber mats, and fibre weed control mats).

Caltrans have undergone massive cuts to their road maintenance budget which has resulted in numerous challenges in managing the roadside environment. The end result is a lot of bare ground ‘moonscapes’ contrasting some high maintenance interchange landscape areas that are maintained with a constant supply of unsustainable potable water.

However, their commitment to innovation with regard to permanent vegetation management approaches, the use of high tech systems to manage water usage in their landscaped areas, and a commitment to using more environmentally friendly herbicides with low active ingredient content is to be applauded.

For Australia, the big taken home message was Caltrans commitment to fund research into better ways of managing roadside vegetation and the hard work being done to ensure that vegetation management considerations are an integral part of the planning and design phases of road and roadside construction.

We would be keen to hear what permanent vegetation control techniques you have put into place. What has worked and hasn’t worked? What are the difficulties of implementing such techniques…is it the upfront cost, are we just not considering these techniques at the design phase? We welcome your comments, questions and feedback.

You will find a selection of images from the Caltrans visit on the IVMP website in the image gallery