UNH T2 Center, Vegetation Control for Safety

Vegetation Control for Safety

Figure B: Vegetation Clearance for Street with Curb and Sidewalk

Trees and shrubs on the roadside can cause result in safety hazards. Establish some height requirements to eliminate low hanging branches and sight distance blockage. These figures may serve as guidelines to establish ordinances for both the road or street and sidewalk.

Speed Limit (MPH)	Noncritical Signs (Feet)	Critical Signs (Feet)
30	150	250
40	200	350
50	250	450
60	300	600

Critical signs are: STOP, YIELD, DO NOT ENTER, ONE WAY, WRONG WAY , and other regulatory signs. Non-critical signs are destination guide signs, parking regulations; advance warning signs, and similar warning or information signs.

During the growing season, grass, weeds, and brush often limit a driver’s view of approaching vehicles. Lush vegetation acts hide

pedestrians and bikers from drivers, and vice versa. Often, vegetation needs to be trimmed.
The main goals for vegetation control include:

Keep signs and vehicles visible to drivers, pedestrians, and bike riders in cross walks, street lights, uncontrolled intersections, and bike paths
Assist pedestrians and bike riders to see oncoming traffic more easily.
Improve winter road maintenance in snow and ice areas.

NH Laws

NH RSA 231:90-231:92 covers liability for roadways. This is commonly known as the 72 hour law. After municipalities have received notification, they must make a plan to correct it within 72 hours.

Line of Sight Clearance

Intersections require a clear line of sight along crossroads to prevent vehicle, pedestrian, and bicyclist collisions. An unobstructed line of sight allows adequate distance for drivers to react safely to each situation. To keep signs and traffic visible follow these suggested maintenance steps:

Look for signs and other traffic control devices blocked by brush, trees, grass or weeds when on routine maintenance patrol. Cut vegetation along the ditch or shoulder blocking a driver's view of signs.
Follow municipal policy regarding the distance from a sign in which vegetation has to be cleared for safe view. The figures and tables are a suggested guideline. The table allows a driver 3-5 seconds to read and respond to a sign.

Sources:

Country Road & City Streets, WV Transporation Technology Transfer Center, March 2003 Vol. 18 No. 1 pgs 1-3
The figures are from a presentation given by Alan Gesford of the Pennsylvania T2 Center.

Winter 2003