From a security standpoint, these vehicle attacks are a bit of a game changer. They are not something we are going to be able to consistently, adequately defend against. We have a limited capacity to 'target harden' major events and the most high profile symbolic targets, but that's about it. As a front line professional in this field, in a city where this is a real concern, this is an attack pattern that I worry about.
These attacks seem to cease in one of a few ways:
- The attacker voluntarily ceases the attack to attempt to evade capture or death; e.g. Belgium a short time ago, or Berlin around Christmas.
- The driver is incapacitated with lethal force, e.g., Nice, Jerusalem IDF attack.
- The driver voluntarily exits to continue the attack by other means like knives or guns, e.g., the Lee Rigby murder.
- The driver crashes (on their own, or with help) and is unable to continue the attack with the vehicle, e.g., the attack in St Jean, Canada, or westminster, or other attacks. This seems to be the most common way the ramming stops, but often precipitates a continued attack by other means.
Stopping a vehicle attack with gunfire is unreliable. You typically won't disable the vehicle in a timely manner. Incapacitating the driver is a chancy thing at best, though quantity of gunfire has a quality of its own.
The driver voluntarily dismounting to evade, or dismounting to shoot/stab isn't an element within our control.
So, what's left that we can impact is making it more likely the vehicle will crash, or being able to pin/crash into the vehicle. A vehicle can be made more likely to crash with permanent or temporary obstacles - bollards, serpentine barricades, vehicles temporarily positioned, etc. Realistically we can only do this in a few cases.
So that leaves us at square one. Some dude goes dirka dirka in a five ton truck, we need to either stop the driver with force, or force him to dismount. This basically leaves emergency responders trying to slow the threat down with our vehicles, block/stop it with our vehicles if we have the mass/horsepower, or slow him down enough that we can shoot him in the face. All of that will take time, and if the target was chosen well, mass casualties will be basically inevitable.
EDIT TO ADD: And just so it's clear, I'm not saying anything here that isn't already broadly known and covered in the media. There's nothing secret about this vulnerability.