Safety Road Barrier

Features & Benefits

# Roadside Safety - Barriers - **leaving the road and hitting roadside hazards, including slopes (roadside barriers)** They are designed to redirect the vehicle and have a lower severity than the roadside hazard they protect. Flexible barriers are made from wire rope supported between frangible posts. Semi-rigid barriers are usually made from steel beams or rails. These deflect less than flexible barriers and so they can be located closer to the hazard when space is limited. Rigid barriers are usually made of concrete and do not deflect. Currently (depending on their height and other details) these provide the highest level of containment of heavy vehicles. Vehicle parapets are rigid barriers in steel, concrete or a combination of both. ###### Barrier end terminals Flaring of beam barriers so that the end terminal is as far as practical from the general barrier alignment Curved-out layout of rigid barriers or masonry parapets at a maximum angle of 40 degrees from the general barrier alignment Sloping end of W-beam barriers of gentle gradient anchored into the ground may be an acceptable treatment. At low to moderate speed, an errant vehicle may ride over the barrier. These openings may be provided by an overlapping barrier layout such that the leading end terminal of the second barrier is shielded by the trailing section of the upstream barrier. - A safety barrier should only be built if the existing hazard cannot be removed (see Roadside Safety – Hazard Removal). - On high volume, high speed divided roads and roads on steep sidelong ground, a continuous safety barrier can be a more appropriate strategy to address continuous downhill side slopes or a high density of hazardous objects. - With the use of continuous barriers, adequate consideration should be given to refuge space for stranded vehicles and their occupants. In general, a shoulder width of 4m to 6m (3m minimum) in front of the barrier is desirable or else lay-bys should be provided at regular intervals. Access openings for emergency or maintenance may be provided with the safety barrier in overlapping layout. - Safety barriers should be located so as to minimize high impact angles and should also allow space for vehicles to pull off the traffic lane. - Ensure appropriate clearance behind safety barrier is considered particularly for flexible and semi-rigid barriers. With concrete barriers although they do not deflect, allowance must be made for any hazards taller than the barrier to be offset far enough from the face of the barrier so that during impact vehicles (particularly high vehicles such as trucks) do not lean over the barrier and strike the hazard - If an uphill slope is not available, additional roadside area will need to be created to accommodate a flared barrier end terminal. - If a flared safety barrier needs to cross a longitudinal ditch, appropriate detailing will be required to avoid an errant vehicle becoming snagged, under-riding or over-riding the barrier.

Technical Specifications