The plan constitutes a “how to” guide for the best way to manage roadsides in any given area. “Washington State has diverse climates and the highways have many neighbors, so the plans vary depending on location,” the state DOT says.

Echoing the mantra of the pavement preservation movement, WS DOT says “[t]he plans determine the right tool or combination of tools, for the right plant at the right place and time,” adding that is the essence of an integrated vegetation management plan.

WS DOT’s vegetation management tools include mowing and trimming, selective use of herbicides, release of weed-eating insects, improvement of soils, re-establishment of native plants, and hand-maintenance by volunteers or contract services. Their use is articulated in regional roadside vegetation management plans for each region inside each DOT district, necessary due to the extreme variation of environments within the Evergreen State, which range from high desert to alpine to urban to coastal rain forest.

Safety, Preservation in Bay State

Massachusetts’s current Vegetation Management Plan, 2009-2013 has a primary objective of providing a safe, unobstructed roadway corridor, and preserving the integrity of the highway infrastructure.

“Management of vegetation is an important element of roadside maintenance for safety and aesthetic purposes,” according to the plan. “Left uncontrolled, roadside vegetation can impede normal maintenance operations, obstruct motorists’ line of vision, threaten pedestrian safety and cause damage to structures such as median barrier, pavements, guard posts, drainage lines and waterways.”

“Left uncontrolled, roadside vegetation can impede normal maintenance operations, obstruct motorists’ line of vision, threaten pedestrian safety and cause damage to structures such as median barrier, pavements, guard posts, drainage lines and waterways.”- Massachusetts’s Vegetation Management Plan, 2009-2013

Other objectives include provision of an aesthetically pleasing roadside, pest control, creation of wildlife habitat, and stabilization of embankments and other areas prone to erosion.

The key components of Massachusetts Highway’s integrated program are identification of priorities for vegetation control, implementation of controls in an environmentally sensitive manner, and monitoring of performance to check methodology.

Like other states, Massachusetts is retaining use of herbicides. “Controls shall include mechanical, chemical, cultural, biological and roadside development methods,” the commonwealth states, adding “[i]t shall be a goal to minimize the use of chemical controls, through minimizing areas of application, quantity of chemicals, and frequency of applications. Chemical control techniques shall be limited to use on high traffic volume, high speed interstate and primary roadways in the commonwealth where safety of motorists, department employees and contractors precludes the use of mechanical methods.”

Mass Highways defines three classes of roadside vegetation:

The State of Iowa is encouraging districts, counties and cities to improve roadsides with its Living Roadway Trust Fund.

• Hazard vegetation represents the primary target material, including vegetation obscuring sightlines, growing over guardrails, creating obstacles to signs or vehicular movement, posing windfall hazards over vehicular or pedestrian ways, or creating winter shade leading to icing conditions.

• Detrimental vegetation, including grasses and woody plants that are destructive to, or compromise the function of, highway structures, including grasses in pavement and bridge joints, medians, barriers and traffic islands, and vegetation growing in and along drainage structures, compromising drainage. Such vegetation creates storm water accumulation and hazardous icing conditions.

• Nuisance/noxious vegetation, including any vegetation growing along state roadways that could potentially cause problems to the general public or Mass Highway employees or contractors, usually poison ivy. Other nuisance vegetation may be growing within 30 feet of the edge of pavement, bridge abutments, a drainage structure or swale, other structures and appurtenances requiring maintenance, within state highway rights-of-way, are considered target vegetation.