Three Letters Re: Real World EMP Effects on Motor Vehicle

I read the report in the government document regarding the effects of EMP on vehicles. The vehicles were only tested at 20k V/m then up to 50k V/m if they survived the first test. The reason that they were not tested beyond 50k V/m is that is what is the “known” maximum that would be released. The Russians have purpose-built EMP warheads that are speculated to emit 1m V/m to 2m V/m (100k V/m to 200k V/m). These weapons would completely destroy sensitive engine management controls. To put this in a little more perspective, the Starfish Prime test in 1962–that blew out street lamps [hundreds of miles away] in Hawaii–was only 5.6k V/m.

Setting all of this aside we still have a greater threat from an coronal mass ejection (CME) from the Sun. If the United States were to be attacked with EMP weapons it would be bad, but localized to our continent, Canada and Mexico would feel some of the results. If we have a massive CME it could have the same EMP effects except worldwide, and at a higher V/m than any weapon could produce. Nuclear weapons emit 50k V/m voltages in milliseconds, a CME hit could last for minutes. If we were attacked it would be possible we could get help from allies, but if it were to be a solar event the whole planet could be in the same boat.
Here is a segment from a Future Weapons episode that shows a vehicle experiencing just such an event, and it does not restart.

This is why I am keeping my non-computer controlled 1980s era 4×4 diesel truck. – The Last Conservative in California

Hi Jim,
Michael Williamson provides some very usable data, and considering the already existing, grounded shielding built-into vehicles, this resistance of automobiles and trucks to EMP makes sense.

However, most EMP measurements I’m familiar with, particularly after a nuclear detonation, occur in the hundreds of thousands, not just tens of thousands of volts. I think we still need to actively prepare for an EMP event. Besides, the way I store my unused electronics (in Mylar bags, placed in ammo cans, connected to earth ground) and electronic motorcycle components also helps to protects them from fire, flood, etc.

While an EMP event would be classified as “seldom” in a risk assessment matrix, its severity would be off the scale, to the point where those of us with anything electronic, and working, would be perceived as gods. Cheers, – J.E.

Dear James,
I’m responding to Michael Z. Williamson’s letter “Real World EMP Effects on Motor Vehicles” regarding the likely outcome for our transportation system after an EMP event. Based solely on the simulations he cited, his is a reasonable view. Unfortunately, simulations aren’t the real world, and I doubt our transportation system would hold up.

In all transportation concerns, I place heavy emphasis emphasis on the word system. It’s reasonable to regard the transportation system as a living organism, and we all know there are numerous ways to kill any organism. In the simulation, all the cars restarted, and that’s comforting. But – one out of 18 trucks had to be towed in for repairs. Here’s a thought experiment based on the 1/18 failure rate: I’m assuming that the disabling damage was to electronics, and that the damage rate held nationwide. First, the backlog for replacement electronic parts would stretch into months or years.

Sure, you’d probably find a handful of electronic control modules (ECMs) or the various sensors for any given engine at truck dealers in any major city. Problem is, there are tens of thousands of trucks in proximity to any major city on any given day. If one out of twenty of those trucks failed, it would take a week or two just to tow them all in to the shops. Available parts would quickly disappear into the trucks towed in first. (The lucky recipients might be the tow trucks, for all we know.) And, if components failed on the truck, who’s to say any replacement parts on dealer’s shelves will be any good? Then there’s the still-running fleet’s need for ongoing repairs, including plenty of their own electronic issues. Sure, those trucks survived the initial burst, but what would happen to the failure rate of their electronics? Also, how will the electronics manufacturers function after EMP? Will they be able to produce more parts, and what’s that time frame? There are further issues, but at least the problem is in focus now.

If one in twenty trucks nationwide were inoperable it would put a serious crimp in just in time (JIT) deliveries. As your readers know all too well, JIT inventories/deliveries are already stretched to the breaking point. Combine that with a bit of nervousness on the part of the unprepared…

Trucks also carry fuel. Minus fuel distribution, the transportation system grinds to a halt in a matter of days. I’ll skip past the distribution challenges, and pipeline/refining SCADA issues (all very real, but hard to relate to) and focus on a link we all know well: gas pumps. When you stick your credit card in that slot, you’re effectively operating an ATM – an ATM that dispenses liquid gold instead of paper money. ATMs depend on a working power grid, along with functioning Internet/telecom and banking systems to operate. Don’t bet on using cash, either – if electronics at the station or in the pump are fried or if the power grid is down, the pump simply won’t run. The brain (car computers) may survive, but if the blood (fuel) doesn’t flow then your car is dead anyway.

In survival planning, we generally deal with icebergs. It’s small comfort that a visible part of this iceberg fared well in a simulation – a government simulation at that! Cars/trucks in close proximity to miles of conductor (power lines, pipelines, rails etc.) may experience much stronger pulses than were simulated. How will they fare, and does it even matter? I say it doesn’t. I remain convinced that the transportation system will collapse after an EMP event, and that it will fail at multiple weak links. At least some of the cascading failures would have nothing to do with the vehicles themselves, and some of those would occur in systems I haven’t even addressed here.

EMP is a grave scenario, and I’m praying we never find out about it firsthand. As always, James, thanks for your yeoman efforts on the SurvivalBlog.

Regards, – Fred H.