Listed in Highway Safety
Keeping roadsides clear and safe goes beyond pavement maintenance. Mowing and vegetation control are essential tasks that help ensure driver visibility and overall roadway safety. Overgrown grass, brush, and tree limbs can obstruct sightlines, block traffic signs, and hide hazards from motorists. A well-planned vegetation management program improves safety, protects infrastructure, and helps your highway department stay in compliance with local and state standards.
Why Visibility Matters
Driver visibility is a critical factor in roadway safety. If vegetation obscures stop signs, curves, intersections, or roadside hazards, the risk of crashes increases. In rural areas, unmanaged growth can hide wildlife or pedestrians near the roadway. Along high-speed roads, even a slight reduction in visibility can significantly affect reaction times.
Key areas where vegetation control impacts visibility include:
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Intersections - Clear sightlines in all directions are vital for safe turning and crossing.
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Curves and Hills - Vegetation can block a driver’s ability to see oncoming traffic.
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Signs - Traffic control signs must be visible at the distance specified by the Manual on Uniform Traffic Control Devices (MUTCD).
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Guardrails and Shoulders - Overgrowth can conceal the edges of the road and guardrail ends.
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Driveways and Side Roads - Visibility at driveway entrances and minor road connections must be maintained.
Mowing Strategies
Routine mowing is the foundation of roadside vegetation control. Departments often adopt mowing cycles based on road classification, visibility needs, and growing conditions:
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Primary mowing during late spring and early summer targets fast-growing grasses and weeds.
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Mid-summer mowing helps maintain clear sightlines through peak growth periods.
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Late-season mowing controls brush and prepares roadsides for winter.
For visibility-related mowing, highway departments prioritize:
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Intersections
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Inside and outside curves
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Sight triangles approaching signs and signals
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Areas with known safety concerns or previous complaints
Mowing is often performed to a standard width from the pavement edge; commonly 3 to 5 feet on low-volume roads and wider on high-speed highways.
Brush and Tree Control
Brush removal and tree trimming are necessary complements to mowing. Branches and tall brush can obstruct long-range visibility, particularly on curves and hills.
Methods include:
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Mechanical brush cutting with rotary mowers, boom mowers, or forestry heads.
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Manual pruning and removal of overhanging branches.
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Strategic herbicide applications (where permitted and appropriate).
Departments must balance safety goals with environmental considerations - retaining beneficial vegetation where possible while keeping critical sightlines open.
Inspection and Recordkeeping
Regular vegetation inspections are essential. Many departments use seasonal “visibility patrols” or combine inspections with other asset checks (such as sign assessments). Areas with persistent growth problems can be flagged for more frequent maintenance.
Maintaining records of mowing dates, locations, and vegetation work is also valuable. It demonstrates due diligence, supports liability protection, and informs future planning.
Mowing and vegetation control might seem like routine tasks, but they play a vital role in keeping drivers safe. An effective program should focus on strategic visibility areas, follow a clear schedule, and document work performed.
By keeping roadside vegetation in check, highway departments protect public safety, preserve roadway assets, and maintain the trust of the communities they serve.