Terrorist are using cars as weapons. How can we protect ourselves?

Westminster Bridge by Katie Chan,
via Wikimedia Commons

In an alarming number of recent terror attacks, the assailants have made use of vehicles to ram or crush their victims. Recently, an attacker killed three people on Westminster Bridge in London by hitting them with a hired vehicle before getting out of the car and fatally stabbing a police officer. Last year on Bastille Day, an attacker drove a truck through celebrating crowds in Nice and killed eighty-four people. These attacks and others would indicate a disturbing trend even without reports the Daesh has recommended the use of vehicles to sympathizers aiming to commit lethal terror attacks.

Nice Bay by Fecchi, via Wikimedia Commons

Shortly after the derisively named "undies bomber" failed to blow up a plane bound for the United States with underwear soaked with explosives, American and international aviation authorities severely restricted the liquids they permitted passengers to carry on board. They had, of course, long forbidden passengers from bringing knives into the cabin of an airliner. Every time a terrorist organization attempts an assault against the civil aviation system, even if they fail, even if they fail in a risible manner, regulators take action. With several terror attacks committed using road vehicles, reports the Daesh has specifically committed to  this method of inflicting casualties, the call for road safety authorities to take some action would seem obvious.

Yet with the experience of lethal terror from surface vehicles, with reports the Daesh have committed to inflicting terror attacks this way, the authorities have apparently issued no regulations. Their failure to act does not come from a lack of potential solutions. A number of auto manufacturers, with Volvo as a major pioneer, have developed collision prevention systems that will override a driver's control inputs and apply the brakes sensors detect a pedestrian or cyclist directly in front of the vehicle. With at least one major terror group calling for its adherents to use road vehicles as weapons, making this tactic more difficult by requiring the installation of collision detection systems would seem an obvious step.

So far, I have seen no moves from authorities in any jurisdiction to require this system on all new cars, much less to call for retro-fitting older models. The expense of requiring a fairly sophisticated electronic system on all new cars may hold them back. The technical challenge of implementing a system an intentional attacker cannot disable may also discourage governments. To prevent a terrorist from disabling an anti-collision system by covering or disconnecting the sensors, a tamper resistant system would have to prevent the operation of the vehicle if it could not get a reading from the anti-collision sensors. That would mean snow, ice or mud on the sensors would immobilize a car, as would a defective sensor. A system that would disable a vehicle that got dirt or snow on the wrong part would prove profoundly unpopular with many motorists. 

Still, a safe car that will not mow down vulnerable road users at the command of a terrorist, a drunk, or an inattentive driver has significant advantages for safety, even if it does not stop determined and well informed terrorists. We can hope our governments do more than they have done so far to prevent terrorists from using cars to inflict mayhem. In the meantime, we will have to content ourselves with the safety measure already in effect: the rules forbid passengers from taking cars and trucks aboard aircraft as cabin baggage.