Roadside Safety - Hazard Removal

Crashes between vehicles which leave the road and roadside hazards are a major safety problem.

Roadside hazards can include

  • trees
  • rock outcrops
  • street furniture such as signs and electricity poles
  • stalls set up too close to the road
  • ravines, gorges and open drains.

    Where possible, roadside hazards should be removed. Trees provide benefits (including shade for pedestrians and reduced soil erosion) but large trees and poles (more than 100mm in diameter) that are close to the edge of the road can be a serious hazard.

    Sometimes hazards that cannot be removed can be replaced by equipment (electricity poles and sign posts) that are designed to collapse on impact and approved by existing standards like EN12767 and Manual for Assessing Safety Hardware (MASH). In other cases, the road can be re-aligned or safety barriers can be built between the hazard and the road.

    • Reduced severity of run-off-road crashes.
    • Reduced road furniture repair costs associated with crash damage.
    • Can improve Sight Distance
    • After roadside hazards are removed, the roadside should be left in a safe condition. Large stumps and deep holes are hazards that may remain after removal of a tree.
    • Replacement of removed trees with more appropriate plants should be considered, otherwise re-growth or soil erosion may affect the site.
    • It is not always possible to remove, replace or put barriers around roadside hazards, particularly in urban areas where space is limited. Reducing vehicle speeds is an alternative solution.
    • Where roadside hazards such as lighting columns and sign posts are to be replaced with frangible posts both their design and location must be be carefully considered in order to reduce the risk of the posts hitting pedestrians and other road users or causing secondary collisions.
    • Frangible posts that contain an electrical supply can be fitted with a pull-out plug to prevent tethering and will also provide electrical isolation on impact.

    Benefits

    • Reduced severity of run-off-road crashes.
    • Reduced road furniture repair costs associated with crash damage.
    • Can improve Sight Distance

    Implementation issues

    • After roadside hazards are removed, the roadside should be left in a safe condition. Large stumps and deep holes are hazards that may remain after removal of a tree.
    • Replacement of removed trees with more appropriate plants should be considered, otherwise re-growth or soil erosion may affect the site.
    • It is not always possible to remove, replace or put barriers around roadside hazards, particularly in urban areas where space is limited. Reducing vehicle speeds is an alternative solution.
    • Where roadside hazards such as lighting columns and sign posts are to be replaced with frangible posts both their design and location must be be carefully considered in order to reduce the risk of the posts hitting pedestrians and other road users or causing secondary collisions.
    • Frangible posts that contain an electrical supply can be fitted with a pull-out plug to prevent tethering and will also provide electrical isolation on impact.

    Did you know?

    Median barriers physically separate opposing traffic streams and help prevent head on crashes.

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    Treatment Summary

    Costs
    Low to medium
    Treatment life
    5 years - 10 years
    Effectiveness
    25-40%

    References

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