In The Future, We’ll Stop Truck Attacks With the Push Of a Button

French police in Nice stopped Thursday’s deadly truck attack only after the terrorist killed at least 84 people. But someday soon, local law enforcement may stop similar vehicle-borne attacks using technologies and tactics developed through hard experience by French and allied militaries.

Over the last decade, the Pentagon has created various devices to stop moving vehicles at checkpoints without harming civilians. Some of could be deployed to city streets, according to one Transportation Security Administration official . Others would need modifications; still others, though technically non-lethal, were a no-go.

Here’s a brief list:

Sound guns

After an al-Qaeda boat crew blew a hole in the USS Cole in 2000, a company called American Technology Corporation developed a method to shoot noise a long way along a relatively narrow channel. They named it the long-range acoustic device, or LRAD. (The company has since changed its name to the LRAD Corporation.) These systems use an array of differently shaped transducers to create sound waves that are lower and flatter than regular amplified waves. That allows the device to focus loud noises — up to and including painfully loud — at a particular spot up to 8,900 meters away.

The LRAD Company makes a version of the device that can be remotely operated, and thus, theoretically, could be positioned on city streets and activated by a police force upon learning of a truck attack. But c ompany officials, who say the device is not intended as a weapon but rather a warning system, say the system is not yet loud enough to stop a terrorist or focused enough to spare bystanders' ears.

The TSA official called long-range acoustics an area “we’re monitoring.” (He spoke to Defense One on condition of anonymity because he was not authorized to discuss current research publically.) “I think it’s an interesting concept in terms of stopping someone.”

The military’s Joint Non-Lethal Weapons Program has been working on a next-generation sound gun that uses direct energy to create a ball of plasma (the fourth state of matter after gas, liquid, and solid) at a specific point in space as many as 100 meters away. The gun would then use subsequent blasts of directed energy to manipulate the plasma ball to create noises of up to up to 130 decibels. People that are close to the ball, a truck attacker for instance, would get the brunt of the noise, but onlookers would be largely spared. ( Defense One has asked Joint Non-Lethal Weapons Program for an update on the research; we'll let you know if we hear back.)

Visual dazzlers

In 2004 , U.S. soldiers in Iraq were seeing roughly one event per day in which cars charged a checkpoint or soldiers fired on approaching vehicles that they believed to be a threat. (Often the drivers simply didn’t understand the commands the soldiers were giving them.)

So the military issued 400 green lasers to soldiers to temporarily blind drivers, an act that’s called “dazzling.” The number of fatal checkpoint incidents decreased dramatically. The military has since issued some 16,000 lasers for checkpoint security.

Sticking dazzler guns on city streets to stop truck attackers is impractical and probably a no-go for legal reasons.

“The problem with something like that is the potential to do physical harm to a subject,” the TSA official told us. “It’s probably non-lethal unless the person has an accident and kills himself. But it would be something we would have to look at from, not only a technical perspective but a legal perspective, would this even be practical for law enforcement to do?”

Active Denial

The same considerations that would keep police from deploying blinding lasers apply to the so-called active denial system, or ADS . It sends millimeter-wave radiation into the skin at about  1/64th of an inch, which is incredibly uncomfortable but otherwise harmless. Though it was deployed briefly to Afghanistan, it was never used.

The military subjected ADS to full treaty and legal review. “These reviews have determined there are no legal prohibitions to the development and use of this technology when it is employed properly and in accordance with appropriate tactics, techniques and procedures,” Kelly Hughes, a former spokesperson for the Joint Non-Lethal Weapons Directorate, told Defense One last year.

But that doesn’t mean that cities can just go ahead and install pain rays on overpasses and not expect to be sued.

“I think that would definitely be challenged legally and ethically” the TSA official said.

Electromagnetic Car Zapping

Modern vehicles are a lot more than internal combustion engines and wheels. Increasingly complex electronic systems play a larger and larger role in nearly every aspect of vehicle operation. If you can fry the 100 plus microprocessors that are common on modern autos, you can stop the car in place.

Military and high security facilities use a system of pre-implanted rods that pop out of the ground and send 150,000 volts directly into cars electronic systems. “They’re effective. They work well,” said the official.

But telling a community board to tear up city streets in order to place electricity roads at street corners to is a tough sell. “When you say city streets, I’m not sure there would be a lawful use case for putting those just at an intersection,” the official said.

What if you could make a temporary version of the system that could be brought in to protect large crowds during high capacity events but then removed? “We haven’t seen anything like that. It would be of interest,” he said.

There’s more than one way to fry a car.

Back in 2010, the Air Force Air Armament Center put out a request for information for a non-lethal car zapper. A company called Eureka Aerospace responded with an electromagnetic pulse cannon, (called the High Powered Electro Magnetic System, or HPEMS,) capable of killing a car’s electronics at a distance of 650 feet.