Prior to recently, the primary use of a barrier was to simply keep explosives-packed vehicles away from structures, as in the attacks on airport terminals like the one in Glasgow. At any transportation hub, kerbside drop-off used to literally mean that, but today we move to a large expanse of tarmac to maintain adequate separation. Having to walk up to a few hundred meters, frequently in the rain, to get a taxi is one of the costs we pay for fighting terrorism. Consider Paddington station in London, where black cabs once descended a ramp into the center of the station; today, one must walk at most a half kilometer to join the line.
Since personal freedom is now regarded as a right, our safety is a concern. However, for any security to be effective, it must impose some restrictions on us. Our politicians will have to make a decision about how much freedom we must give up in exchange for safety, but we must stop terrorist organizations from using any new strategies to harm us.
It is simple to suddenly swerve off the road, mount the sidewalk, and strike pedestrians with a car. From the attacker’s point of view, the attack is more effective with larger, heavier vehicles. Hostile Vehicle Mitigation (HVM) has long been a priority for some organizations, such as the military, but it is now a priority for many public bodies and ought to be on the agenda for many commercial organizations. Maintaining a secure perimeter is crucial, and while doing so has a cost, doing nothing runs the risk of cost; for commercial bodies, the expense of liability litigation should prompt them to consider HVM.
Physical separation is the only way to prevent vehicles from ramming into crowds, and the idea of portable concrete barriers has advanced to the point where such solutions are easily accessible. These fixes might not look good in the beginning, but they are very useful and, in more long-term installations, can be painted or landscaped to enhance the view. They can even be made to pay for themselves by renting out the space on for advertisements, which could be a strong selling point for a venue that hosts sporting events or other types of entertainment.
There is no doubt that they are effective; in fact, I have witnessed numerous examples of them in action.