One Way Network

By removing one direction of traffic from a network, the risk of crashes can be reduced.

This can be achieved through a reduction in conflict points at intersections, and may make pedestrian crossing movements easier with more orderly gaps in traffic.

One-way traffic systems are often used to replace 'grid' street patterns to

  • reduce congestion problems in city centres
  • create access-only streets (usually for access to residential uses).

    However, drivers may become used to the lack of opposing traffic and increase their speed. Also, one-way networks can be confusing for non-locals and increase travel distances.

    • Reduced pedestrian crashes (pedestrians only need to look for traffic in one direction, and there are more orderly gaps in traffic).
    • Reduced head-on and intersection crashes.
    • Can allow better traffic signal timing.
    • Because speeds can increase on one-way networks, traffic calming measures may be required (especially if the lanes are wide).
    • Before a network is made one-way, traffic circulation in the area surrounding the network must be considered.
    • Converting a network to one-way can be costly as it may involve rebuilding traffic signals, repainting linemarking and replacing and adding signage.

    Benefits

    • Reduced pedestrian crashes (pedestrians only need to look for traffic in one direction, and there are more orderly gaps in traffic).
    • Reduced head-on and intersection crashes.
    • Can allow better traffic signal timing.

    Implementation issues

    • Because speeds can increase on one-way networks, traffic calming measures may be required (especially if the lanes are wide).
    • Before a network is made one-way, traffic circulation in the area surrounding the network must be considered.
    • Converting a network to one-way can be costly as it may involve rebuilding traffic signals, repainting linemarking and replacing and adding signage.

    Did you know?

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

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    Treatment Summary

    Costs
    Medium
    Treatment life
    20 years +
    Effectiveness
    25-40%

    References

    • iRAP Road Attribute Risk Factors - Median Type.
    • Towards Safer Roads, p30; 116-117.
    • Austroads (2002-07) Road Safety Risk Assessment Project.
    • Elvik, R., Hoye, A., Vaa, T. and Sorensen, M (2009) The Handbook of Road Safety Measures, 2nd edn, Emerald Group, United Kingdom.
    • Ogden, K. W. (1996) Safer Roads - A Guide to Road Safety Engineering. Avebury Technical, Ashgate Publishing Limited, Grower House, Croft Road, Aldershot, England.

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