Stopping Car Bombs in Iraq

Believe it or not, my father is the leading medical researcher on intestinal gas (which has earned him the moniker the “King of Farts” — see here, and here). Two of his fart-sniffing employees recently earned the honor of “worst job in science” in Popular Science magazine for their efforts on his behalf.

Which I suppose makes him a rogue physician.

But, that is not the point of this post. Anyway, he has good ideas on lots of topics, not just gas. We got to talking about the current situation in Iraq and he made the point that we should have some technology for figuring out which cars are loaded with car bombs.

So let me throw some questions out to those who are knowledgeable in this area:

1) How much explosive is in these cars they are using to blow things up? Are these cars packed full of explosives? How much would the explosives weigh relative to the natural weight of the car? Would a car packed with explosives have a much higher density/weight per wheel than the typical vehicle?

2) Are there existing technologies for measuring the density of an object at a distance that could be used to remotely detect these vehicles?

3) Could we use sensors in the road to pick up indicators of vehicles with lots of weight per wheel?

4) Are there visual clues, like the weight of the explosives making the vehicles ride really low?

5) Any other great ideas for how to identify car bombs from a distance?

If the readers of this blog show half as much talent on this topic as they did on searching out the origin of the term “Chicago Black Sox,” we may save some lives in Iraq.

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  1. USMA03 says:

    Dr. Levitt,

    I am really interested in your and the community’s thoughts on this post because I recently had one of my close friends from West Point injured in a suicide car bombing outside of Mosul. I would love to have some fresh ideas that I could implement when I go to Iraq this winter or send to my friends already there.
    Currently I’m an Artillery Officer in the Fourth Infantry Division and I don’t claim to know a ton about explosives in suicide car bombs, but here is my attempt at answering your question:

    1) How much explosive is in these cars they are using to blow things up? Are these cars packed full of explosives? How much would the explosives weigh relative to the natural weight of the car? Would a car packed with explosives have a much higher density/weight per wheel than the typical vehicle?

    As you can imagine, some explsoives are lighter than others – notably the ones from the plastic explosives family (C4, Semtex, etc). These types of explosives are relatively light (I carried a backpack of C4 once and don’t remember it being heavy) and extremely powerful. Fortunately, these explosives are also very expensive and hence much harder to come by.
    The most common type of explosive is a series of daisy-chained 155mm artillery shells. This type of shell is relatively heavy, approximately 100 pounds, and takes up a lot of space, roughly 4 foot high and a foot at the base. This type of car would be more conspicuous if it were in the cab/passenger area, so it follows that they would try to conceal it. I speculate that you could probably fit 12 or so in the trunk of a midsize sedan. A car doesn’t need to be loaded with a ton of these to be effective since it has a kill (burst) radius of 50m when fired from an artillery piece. However, it is in a car which must severly contain its effective range. I definetly think an axle weight breakdown might work on 155mm based car bombs, but I’m unsure on a plastic explosive based one.

    2) Are there existing technologies for measuring the density of an object at a distance that could be used to remotely detect these vehicles?

    No Clue.

    3) Could we use sensors in the road to pick up indicators of vehicles with lots of weight per wheel?

    I know of two types of scales we use to deploy from CONUS – one is akin to the weighing station at a highway stop, you drive onto the scale and wait for a minute or so and it weighs the total vehicle and axel weight breakdown. This one would be expensive and probably only used at fixed installations (bases). Another is a drive on scale that uses four independent sensors/scales to weigh the vehicle. This type could be used at impromptu checkpoints.
    We could definetly install scales at a distance and maybe use a stop-light like system to tell them the vehicles is weighed and they can come forward. The only drawback I see to that is the possible vehicular congestion; that might make the Iraqis that actually work on the base/stuck in a checkpoint more susceptible to attack by insurgent forces.

    4) Are there visual clues, like the weight of the explosives making the vehicles ride really low?

    I would definetly say that a lot of 155mm shells would make a vehicle ride low, only problem might be a vehicle that is “lowered” like in America or one with rusted/busted shocks that cause it to ride lower. Same criticism could be applied to my vehicle handling idea below.

    5) Any other great ideas for how to identify car bombs from a distance?

    Maybe another way to identify at a distance might be vehicle handling (the chasis’s angle from the vertical plane in a turn at a controlled speed). Almost all of the checkpoints have concrete blocks (like the ones used in highway construction to prevent cars from going into the work area) that force cars to make severe S turns to get to the gate/inspection point. I would imagine that a vehicle loaded with heavy 155 shells would leer a little when approaching the turns at checkpoints.

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  2. In my opinion, focusing on the weight and driving attributes of the car bombing vehicle might be as effective as simple observation.

    For instance, it is likely that an individual participating in a car bomb will be driving by themself. Therefore, cars with just a single individual should receive at least a little more scrutiny that a person driving a vehicle full of passengers.

    I think another useful tool might be to profile types of vehicles that are often used in car bombings. I have not seen any particular types of vehicles used in car bombings and will not claim to know, but I am fairly certain that particular types of vehicles are used in such attacks. A small and light sedan, for instance, might be as effective as a slightly larger sedan. Perhaps maybe even the age and appearance of the vehicle could play a role in its likelihood of carrying bombs. Maybe car bombers are more likely to use older vehicles for such attacks, or vice versa.

    Focusing merely on weight might be a bit difficult to apply in actual situations. Pulling cars over to the side and asking them to have their car weighed is not only intrusive, and may offend law abiding citizens, but may not even prove partially effective (car bombers may readapt their tactics).

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  3. Anonymous says:

    I know you guys have a real problem getting mixed up with Malcolm Gladwell, but I think this might be a situation where some of the lessons of “Blink” might be useful.

    I’m wondering if there’s some way of taking high-resolution photographs of a driver’s face and then have that photograph analyzed for signs of stress, anxiety, etc. in real time.

    I don’t think that existing face recognition software is sophisticated enough, so you’d have to have some highly-trained individuals doing the analysis.

    Maybe over time, these individuals would be able to instantly “see” a car bomber just from a face photograph.

    The terrorists can change the type of explosives and techniques they use, but they’re always going to need a driver.

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  4. Crazy says:

    Great comments already (not unexpected as people who post first tend to be diehard fans of Freakonomics). I just want to add that in the Italian Job(2003) there were three identical armored trucks travelling and only one of them had real cargo. The thieves hacked into a traffic camera and visually measured the height of the tires in order to figure out which one was riding low.

    Given what USMA03 said, the problem is that the explosives aren’t necessarily that heavy. Does anyone know what is the distribution of explosives used in Iraq car bombings and their success/failure?
    I know they are using bomb sniffing dogs in Iraq, but apparently their effectiveness can be hampered by the heat.

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  5. Thomas Miller says:

    Many of these bombs are detonated by radio control. It seems we have the technology to “bradcadst” radio signals across all frequencies from a lead vehicle in a convoy that could detonate car bombs before our troops get too close. Of course this may not be good for any hapless civilian near the car at the time.

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  6. TheJew says:

    200 pounds of dynamite is 200 pounds of dynamite. The difference between a full twenty gallon tank of gas and a quarter tank is about one hundred pounds. A gallon of milk weighs about eight pounds. So, the difference between an unloaded sedan and a sedan with a full tank of gas, ten sacks of groceries and a spare tire is about the same as the difference in weight between an unloaded sedan and a car bomb with enough explosives to demolish a ten story building. As a visual demonstration, the person who did this only used as much explosive as could fit into a back pack and be carried on his person.

    More generally I have addressed the essential problem we face in Iraq here. Since it’s long, I’ll summarize: By making the central authorities more directly responsive to the people (as opposed to relying on intermediaries like “community leaders”), the people will feel a greater sense of control over the government and will therefore feel more invested in its success. Specifically, in a macro context the judicial system must be strengthened so that individuals will see a response to their grievances (including and maybe especially against US citizens). In the micro context, improving telephone networks would allow people to call the government or other authorities to get an immediate response to emergent problems. The key is to make the authorities interact as directly with the people as possible. If we work through intermediaries, even “democratically elected” intermediaries, we simply transfer authority and legitimacy to them, allowing them to wield it against both ourselves and the Iraqi people in pursuit of their private interests.

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  7. TheJew says:

    I forgot to include a couple more things about bombings of US service personnel. It is my understanding that the far greater danger is posed by improvised explosive devices, like a piece of dynamite wired to a cell phone hidden in a pile of trash on the side of the road. Some US vehicles (especially those in VIP convoys) use radio jamming devices to prevent wireless signals from reaching any IEDs nearby, and also knock out civilian cell phone service for a few blocks in every direction.

    Military grade thermal imaging may be able see things like recently fired weapons inside cars, but unexploded explosives don’t look a whole lot different then rocks or any other inert substance (like dry goods in a paper sack) when their shadow is viewed by thermal imaging inside a car. It is possible that a radiation could be discovered for different types of explosives that would cause the explosive substance to fluoresce, which could maybe have some application if it doesn’t also cause cancer. Radiations that are indicative of explosive substances through their absorption would need some way of detecting the shadow of explosives. They have to use similar techniques to ones used to examine (a miniscule proportion of) shipping containers, with something like a gamma ray emitter on one side and a sensor of some sort on the other side. In Iraq, the US seems to want to avoid the close contact with random Iraqis that would be required to scan large numbers of vehicles.

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  8. I’m not an expert on explosives. However I have read of bomb sniffing devices that are fairly accurate. These devices would most likely have to be fairly close to the object it was sniffing, so these devices would have to be planted along the roadside, much like the IED’s that have been devastatingly used by the insurgents. These devices could then be uplinked via satellite. This technology already exists and is more humane than using the more sensitive bomb sniffing dogs.

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