“Concrete and water filled plastic road safety barriers are used on the road all the time and are crash tested, so they are must be an effective protection for hostile vehicle protection, right?” Wrong.
This is a comment we often hear at Protective Barriers Australia when discussing hostile vehicle mitigation for temporary crowded public places on roads such as festivals, parades, community events, etc.
It’s a dangerous myth that needs to be busted so read on to find out why you need to know the differences between PAS 68 & IW 14-1 rated Vehicle Security Barriers (VSB), often referred to as a Hostile Vehicle Mitigation (HVM) Barrier and the traditional “Jersey Barrier” or other Road Safety Barrier.
Hostile Vehicle Mitigation
Vehicle Safety Barrier Crash Test
Road Safety Barrier Crash Test
The major differences between PAS 68/IWA 14-1 rated Hostile Vehicle Mitigation, and the traditional Jersey road safety barrier tested to the National Cooperative Highway Research Program 350/Manual Assessing Safety Hardware rating, is their purpose and the standards and testing method used to rate each type of barrier.
Vehicle Safety Barrier (VSB) – These are designed, tested and certified to provide protection from vehicles coming head-on. Both the PAS 68 and IWA 14-1 rate the vehicles impact approach angle at either 90 or 45 degrees. As shown in our Modular Vehicle Barrier crash test image here.
Road Safety Barrier – Concrete and water-filled jersey barriers are designed to deflect or redirect vehicles in a path parallel to the barrier system. Keeping the vehicle from veering off the trafficable lane. Tested to the National Cooperative Highway Research Program 350 (NCHRP 350) /Manual Assessing Safety Hardware (MASH). With the NCHRP 350/MASH testing the impact approach angle from 0 to 25 degrees, reflective of a deflection back into the lane. As shown in crash test image here.
These differences in the vehicle approach angles require each respective barrier to be designed differently in order to meet the testing criteria of each standard.
Road safety barriers such as concrete, steel and plastic water filled jersey barriers are designed to deflect vehicles from leaving the roadway or trafficable lane. These barriers are generally surface mounted and suitable for use as re-deployable traffic calming devices.
Caution must be taken not to use jersey barriers outside of their design specifications.
From the Hostile Vehicle Guidelines for Crowded Places (ANZCTC, Australia New Zealand Counter Terrorism Committee)
The two key issues
1.Effectiveness in stopping a vehicle head-on
Road safety barriers are effective redirecting a vehicle veering off a trafficable lane however have not been designed, crash tested or certified under the VSB international standards of IWA-14 or PAS 68 for a head on impact
To illustrate, there has been some crash testing of concrete placed on the road in Germany, demonstrating the ineffectiveness. With no anchoring the concrete simply slides across the road surface. See testing footage here.
2. Use Outside Design Specification
The Hostile Vehicle Guidelines specifically make the point that “caution must be taken not to use jersey barriers outside of their design specification” So what is the design specification? As illustrated in the images below the product is designed to be installed joined up in a longitudinal formation so when a vehicle veers off the roadway or lane, it is deflected back in.
However, for use as Hostile Vehicle Mitigation at events, Road Safety Barriers are often used outside this design specification, at a right angle (head on impact position) to block off roads and control vehicles and crowds.
Using the right barrier for the right job
As in any industry and with any product, if the decision is made to use a product outside of its design specification and an incident does occur, who is liable? In the case of HVM if the worst were to unfortunately happen the corner, courts and / or investigator would likely ask – Why deploy outside the product design specification and in contradiction to the Hostile Vehicle Guidelines?
The use of road safety barriers, such as Jersey Barriers, can play a role in HVM. These can include being used as a Traffic Calming device (as outlined in the Hostile Vehicle Guidelines)as a complementing layer of defence against Hostile Vehicle Attack, though not a primary VSB. Alternatively, they can be an effective tool to separate pedestrians from vehicles in the way in which their use is intended, in accordance with their product design specification.
Roads Authorities throughout Australia will not approve barriers for use on the roads unless they are tested and certified to the NCHRP 350/MASH standards. Equally barriers deployed for HVM protection need to be crash tested and certified to VSB Standards (PAS 68/IWA 14-1) standards to be used as an effective measure against hostile vehicle attacks and keep the public safe.