well, the question says it all. How big a vehicle would it take to lug it around?
like a criminal or terrorist can’t figure out they need an older vehicle to drive around in.
Yeah, it will stop a car with a PCM and electronic fuel injection. It is not going to stop a car with a carburator and mechanical distributor.
I don’t have any statistics available but I doubt the majority of high speed police chases here in the United States involves antique automobiles with purely mechanical parts. So while I suppose a criminal could pick a car built before the 1970s I just don’t see one selecting a forty year old vehicle over something more recent. It seems to me that such an emp device would be useful against the majority of vehicles on the road today. The fact that it probably won’t work on an antique car isn’t really a problem.
Not for a criminal. Once these things go on-line then it will happen. And beyond that the computers can be shielded. What it will stop is a car thief who steels a modern car.
I wonder how many car chases are the result of actual planned crimes though. I’m betting the vast majority are entirely shocked to find themselves in this position.
That said, it shouldn’t be difficult at all to shield against. . .
I highly doubt any criminal who gets in a high speed chase ever expects to do so. My guess is that it is a spur of the moment decision, either because they carjacked someone or their planned robbery went bad and they had to get away in their normal every day (modern) car.
Even in the ‘Fast and the Furious’ world that is being imagined here, I would think the typical criminal thinks “and I need a car to get away after the crime”. Some of them may go a step further and say “and I need a FAST car to get away after the crime”. I really don’t see any criminal taking the time or effort to say “and I need a FAST OLD car or one with military grade EMP shielding to get away after my crime”. Either option is likely very expensive and specialized such that a criminal can’t readily get his hands on one or have the money to buy one. The whole reason the three gang members who decided to rob a pawn shop did it is because they don’t have real jobs and needed the money.
I can’t recall the last time I heard of a terrorist who was captured (or escaped) following a high-speed car chase. They’re probably not the demographic that this device was intended to deal with.
The criminals who get involved in high-speed chases are junkies who have a a few hits of meth in their pocket when they execute a moving violation in sight of a cop, or the drunk who is driving on a suspended license. In other words, people who have very limited mental and fiscal resources, and therefore aren’t likely to take the trouble to plan ahead and source a carburetted vehicle (or implement robust EMI shielding countermeasures on a late-model vehicle). These are the people for whom an EMP cannon might be useful in ending hi-speed pursuits before bystanders get killed.
But there* are *evil super villains, there are! I’ve seen the movies.
And they are going to get themselves a '70 Chevelle and be unstoppable. 
I find the idea very interesting, though I wonder how discriminating / targeted it is – if the police use it on a car they’re pursuing, and the bad guy’s car happens to be passing near my car on the highway at the time, are all of the electronics in my car going to get fried, too? (And, speaking of that…I wonder how much it costs to repair a car which been EMPed?)
I wouldn’t even be too sure that it will stop a computer controlled car. A car’s body acts like a somewhat imperfect Faraday cage giving the computer a fair amount of protection. The computers are also designed in such a way that they are somewhat protected from EMPs just so that they can be rugged enough to operate in a car’s electrical environment and also so that they won’t be affected by cell phones, CB radios, and the like.
They have been playing around with EMPs to stop cars since at least the 1970s, and they have always worked under controlled conditions but haven’t performed so well out in the field.
They did essentially the same test as in the video linked by Machine Elf back in World War II to show how their newfangled 1940’s style death ray (heh) would make the enemy bombers just DROP OUT OF THE SKY!!! Have you heard about such a weapon being used in WWII? Probably not, because against real planes it didn’t really work, for much the same reasons as why it won’t work very well against a modern car.
Show me one that will reliably stop cars in a random uncontrolled environment and I’ll be impressed. Don’t just show me yet another controlled environment success because I’ve been seeing those for decades.
I was wondering the same thing. I can’t imagine that the EMP projector would be too precise, which would make it harder to aim… so it would probably disable every car for some distance around the target. Perhaps there would be accompanying police tactics to isolate the target and get other traffic away from it?
Edit: and if cars are somewhat shielded, does that mean that all the things like laptops, cellphones, medical equipment, etc, in the passenger cabin are more vulnerable? Imagine the liability if the EMP fries a passerby’s pacemaker and they die!
Knowing American cops, there’s no way they’re deploying this thing until it comes as a menacing-looking color-matched movable hood-mounted turret and fires with a really cool sound effect.
Expect a number of claims that accidents were caused by EMP, that just coicidentally occured while the driver was drunk or texting at the same time. Also, since this doesn’t appear to stop cars, just the engines, expect speeding cars hit with this to go out of control and crash into things. This sounds like it was invented by CNN to enhance the entertainment value of their coverage of high speed chases. I’ll be busy building Faraday cages for the electronic modules in my cars.
Re: Surrounding vehicles, etc.
Keep in mind though, that every lightning strike produces an EMP blast, and those happen all the time. So it takes quite a powerful, focused hit to make a difference.
Not for a criminal, what? Also, what is “it” that you are referring to?
I remember (in the late 90’s?) seeing survivalists talking about how to shield the computer of your car against EMP. This was intended to keep it working after being in the vicinity of a nuclear attack though.
Although it is possible to create a directional pulse by using a waveguide (if the wavelengths of the pulse fall within a sufficiently narrow band) or by using a device to produce coherent pulses (e.g. a maser), I suspect that any practical device will have enough divergence and energy in side lobes that it would effect other electronic devices in the area in an erratic fashion. As for repairing the damage from a high energy pulse, you essentially have to replace the electronics; not only the engine control module, but any ancillary controllers, data buses, entertainment system, environmental controls, navigation, cellular and satellite communications, et cetera. This would likely be a significant cost of the vehicle, which renders this tool impractical for for general civilian law enforcement use. It seems more useful as a battlefield weapon where the collateral effects are of less concern from a liability standpoint.
There are a few misnomers here. First of all, a Faraday cage (an enclosed conductive cage of metal mesh) insulates against static electrical fields, but may provide only limited protection against electromagnetic radiation (depending on the completeness and fineness of the mesh) and does not insulate at all against magnetic fields. Devices within a cage may be subject to electromagnetic pulses of high frequency even if it is currently enclosed if radiation can enter through gaps such as doors jambs or cableways, and can definitely develop a pulse that enters via a conductor outside the case. It is also subject to induction within the case via a moving or changing magnetic field, which may either be generated directly by the pulse or as a response from conductors outside the case.
Second, the body of a car makes a very poor Faraday cage as it has huge gaps in the conductive surface, and provides almost no protection against radiation in the wavelengths of concern, as it is electromagnetically transparent in those gaps, which you demonstrate any time you use a cellular phone inside a car. Virtually all cars also have a collecting device (antenna) which connects directly to the car’s radio or communication systems. These systems are typically not fully isolated from other electrical systems, i.e. they all connect to a common ground, so any level of voltage developed that exceeds allowable throughput to ground can be delivered to all of the vehicle electrical systems, especially in the high frequency range.
It is true that vehicle control electronics are generally protected against the high frequency noise such as cellular signals and any interaction of other systems, the most powerful of which is generally the starter solenoid, but this is generally done by placing adequate physical separation from the systems, providing adequate ground with isolation against back voltage, providing noise filtering capability within a digital system, and whatever minimal shielding a designer can get away with. These are intended to protect against the milliwatt-range inputs that create noise. An electromagnetic pulse, on the other hand occurs at farfield power densities the high tens of KW/m[sup]2[/sup] to MW/m[sup]2[/sup], and basically acts by inducing resonance modes within an electrical system which causes it to accumulate static charge or current at high frequency until it reaches a breakdown limit.
Wit the exception of electronics specifically designed to operate in a high radiation environment (such as spacecraft avionics) the noise-protection, isolation, and physical and logical hardening features of most commercial electronics simply cannot cope with the power densities developed by high energy electromagnetic pulses, and undergo dielectric breakdown well before the 50kV atmospheric saturation limit. Indeed, efforts to make commercial electronics more energy efficient have also largely made them more sensitive to external interference and pulse damage. Military avionics and hardened electronics have special design features including elaborate isolation and robustness. In other words, they aren’t protected from experiencing the effects of the pulse so much as assuring that they don’t suffer damage from induced currents and high voltage breakdown.
It is true that lightening causes electromagnetic pulses as a result of the dielectric breakdown of air, but because of the way the charge is distributed the pulse is fairly diffuse, and the power density of the pulse is several orders of magnitude smaller than that necessary to induce the damaging resonance that allows accumulation. (When you see a single lightening strike, what you are really seeing is a series of discharges which tend to follow the same previously ionized path to ground, but which appear to the naked eye to be a single discharge.) Lightening is powerful enough to disrupt radio communications, but unless there is a conductive path to equipment (e.g. lightening strikes an antenna or power line) it is almost impossible for pulses from lightening to damage even unprotected electronics.
Stranger
They’re called drug dealers and would certainly pony up the money to shield a car that is hauling millions of dollars of inventory.
I would say that the majority of car chases in my area fall into 2 categories: people with suspended licenses and car thieves. Both categories are unlikely to pre-plan.