A circuit board card is shown, with a blue panel on one side. On the panel are switches and an RS-232 port.

Spoofing An Emergency Traffic Preemption Signal

March 8, 2026 by Aaron Beckendorf 37 Comments

There’s a well-known movie trope in which a hacker takes control of the traffic lights in a city, causing general mayhem or creating a clear getaway path. Unlike many Hollywood representations of hacking, this is actually possible in principle; many cities install Emergency Vehicle Preemption (EVP) systems in their traffic signals to turn them green when an emergency vehicle is approaching. To see what it would actually take to control one of these, [xssfox] reverse-engineered a Strobecom II EVP system.

Most EVP systems, particularly older ones, use a strobing infrared light to alert a traffic signal to an approaching emergency vehicle. To avoid misuse, vehicles often encode a vehicle ID in the infrared signal. There have been some claims that a Flipper Zero can trigger these systems, but none that were well-verified, and probably with good reason; anyone actually trying this against a live system is courting serious legal trouble. To see whether this was actually possible [xssfox] obtained real hardware and tried to reverse-engineer the infrared protocol.

There are two main manufacturers for optical EVP systems: GTT Opticom and Tomar Strobecom. [xssfox] managed to buy a Tomar power supply which handled the processing for signal transmission, and which worked with Opticom systems. Looking at the output of this revealed that it encoded data by skipping pulses, which should be simple enough for Flipper Zero to replicate.

To reverse-engineer the Strobecom protocol, [xssfox] managed to buy a Strobecom optical signal processor, which would normally detect an emergency signal. This worked by modulating the length of infrared pulses. After some brute-forcing, a transmitter using an Arduino Nano and an infrared LED managed to activate the preemption signal, and even to transmit a vehicle ID. It seems that Strobecom systems, at least, are fairly demanding in terms of the signals they accept; signals had to be precisely timed, and in at least some systems, a valid vehicle ID would be needed to change the light.

If you’d like to learn more, we’ve gone into the technology of North American traffic signals before.

How Safe Are Old Airbags, Anyway?

February 23, 2026 by Lewin Day 56 Comments

Automotive airbags are key safety devices that aim to reduce injuries and mortality in the event of motor vehicle accidents. These rapidly-inflating cushions act to soften the blow of an impact, catching occupants of the vehicle and preventing them from hitting hard parts of the vehicle’s interior.

Airbags are rigorously tested to perform as faultlessly as possible under all conditions. However, no system is perfect, and every automotive component has an expected service life. The question is—how old is too old when it comes to airbags? The answer is not exactly straightforward.
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Can A Scan Tool Kill A Car?

February 15, 2026 by Maya Posch 32 Comments

It’s no real secret that modern-day cars are basically a collection of computers on wheels, which also means that we get all the joys of debugging complex computer systems and software with cars these days. Rather than a quick poke under the hood to rebuild a carburetor and adjust the engine timing by hand, you’ll be pulling out a scan tool to gain access to the computer and figure out why the darn thing won’t start after someone else used a scan tool on it, as happened to [DiagnoseDan].

The question was whether the third-party scan tool that was used by the owner had done something to the software settings that would prevent the engine of this 2012 Renault Megane RS from starting, such as erasing keys, or if it was something more subtle. With no stored fault codes and the engine having healthy fuel, spark, and cam sensor readings, the conclusion was that the ECU was not doing its fuel injector things for some reason.

Ultimately, the root cause was that the ECU had been modded, with a re-mapping performed in 2020, meaning that the scan tool that [Dan] was using couldn’t properly interact with the ECU. Reflashing the ECU with the original manufacturer’s firmware was thus the next step, which is pretty involved in itself.

Reinstalling the OS on the car proved to be the solution. Likely, the modded firmware had stored some fault codes, as the ECU normally doesn’t start the engine if there are active codes stored. The third-party scan tool was thus likely blameless, but the inability to just clear fault codes was the real issue.

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Tech In Plain Sight: Finding A Flat Tire

January 21, 2026 by Al Williams 31 Comments

There was a time when wise older people warned you to check your tire pressure regularly. We never did, and would eventually wind up with a flat or, worse, a blowout. These days, your car will probably warn you when your tires are low. That’s because of a class of devices known as tire pressure monitoring systems (TPMS).

If you are like us, you see some piece of tech like this, and you immediately guess how it probably works. In this case, the obvious guess is sometimes, but not always, correct. There are two different styles that are common, and only one works in the most obvious way.

Obvious Guess

We’d guess that the tire would have a little pressure sensor attached to it that would then wirelessly transmit data. In fact, some do work this way, and that’s known as dTPMS where the “d” stands for direct.

Of course, such a system needs power, and that’s usually in the form of batteries, although there are some that get power wirelessly using an RFID-like system. Anything wireless has to be able to penetrate the steel and rubber in the tire, of course.

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The Rise And Fall Of The In-Car Fax Machines

January 7, 2026 by Lewin Day 53 Comments

Once upon a time, a car phone was a great way to signal to the world that you were better than everybody else. It was a clear sign that you had money to burn, and implied that other people might actually consider it valuable to talk to you from time to time.

There was, however, a way to look even more important than the boastful car phone user. You just had to rock up to the parking lot with your very own in-car fax machine.

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Nixie Tube Dashboard Is Period-Appropriate Hack To Vintage Volvo

December 24, 2025 by Tyler August 10 Comments

There’s no accounting for taste, but it’s hard to argue with The Autopian when they declare that this Nixie tube dash by [David Forbes] is “the coolest speedometer of all time” — well, except to quibble that it’s also the coolest tachometer, temperature gauge, oil pressure indicator, and voltmeter. Yeah, the whole instrument cluster is on [David]’s Volvo PV544 is nixified, and we’re here for it.

He’s using a mixture of tubes here– the big ones in the middle are the speedo and tachometer, while the ovals on either side handle the rest. There’s a microcontroller on the front of the firewall that acts a bit like a modern engine control unit (ECU) — at least for the gauges; it sounds like the Volvo’s engine is stock, and that means carbureted for a car of that vintage.

The idea that this hack could have been done back in the 50s when the car was new just tickles us pink. Though you’d have probably needed enough valves to fill up the boot, as our British friends would say. Translate that to “enough vacuum tubes to fill the trunk” if you’re in one of the rebellious colonies.

We’ve featured [David]’s projects previously, in the form of his wearable video coat. But his best known work is arguably the Nixie Watch, famously the timepiece of choice for Steve Wozniak.

Thanks to [JohnU] for the tip!

All images by Griffin Riley via The Autopian

Chinese Regulators May Kill Retractable Car Door Handles That Never Should Have Existed

November 26, 2025 by Lewin Day 157 Comments

Headlights. Indicators. Trunk releases. Seatbelts. Airbags. Just about any part of a car you can think of is governed by a long and complicated government regulation. It’s all about safety, ensuring that the car-buying public can trust that their vehicles won’t unduly injure or maim them in regular operation, or in the event of accident.

However, one part of the modern automobile has largely escaped regulation—namely, the humble door handle. Automakers have been free to innovate with new and wacky designs, with Tesla in particular making waves with its electronic door handles. However, after a series of deadly incidents where doors wouldn’t open, regulators are now examining if these door handles are suitable for road-going automobiles. As always, regulations are written in blood, but it raises the question—was not the danger of these complicated electronic door handles easy to foresee?

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