They’re Not Broken: Why Some Red Lights “Flash” in the Hudson Valley

It was a question I've always asked myself ever since I saw my first one in Stone Ridge, NY back in 2005: "what is wrong with that stoplight?", I would think. Turns out, nothing at all.

"Flashing" Red Lights in the Hudson Valley, NY

If you're a driver in the Hudson Valley, you've seen these on your commute. Every so often, instead of a solid red traffic light, there's a strip of bright-white light that flashes on and off. I just passed one today on Route 9 in Fishkill, NY near the intersection with 84. No, it's not a malfunction, and the red light isn't cracked, either. There's a very special, and intentional, reason why you see those flashes of white light, and it could actually help save somebody's life.

High-Visibility Traffic Lights

It took a lot of digging, but there are two possibilities for the "flashing" red lights. The first is to simply alert motorists of the presence of the traffic light. Often when there's a "first" traffic light after miles of no traffic lights, a strobe is added to grab a motorist's attention.

Another reason is to warn drivers about an approaching emergency vehicle. Dubbed a "strobe-enhanced traffic light", they are also often mounted on top of traffic lights. The white lights flash to announce that an emergency vehicle will soon be passing through. This leads to another question... how do emergency vehicles deal with red lights? The answer is pretty cool.

Mobile Infrared Transmitters in the Hudson Valley

Precious seconds (or minutes) can be lost when first responders need to wait for a traffic light to turn green, and while legal, it's always dangerous for emergency vehicles to drive through a red light, even with their sirens on and lights flashing. That's where a cool device comes in that actually helps traffic lights turn green.

How MIRTs Work

Many traffic signals communicate with a device in the emergency vehicle called a Mobile Infrared Transmitter (MIRT). When they interact, it signals the traffic light to turn from red to green (and turns the other traffic light from green to red), to allow the firetruck, ambulance, or police car to pass through intersections more quickly and safely.

Speaking of "safely" (and the police), MIRT devices are illegal for public use. This may be stating the obvious, but you can imagine the commute chaos if red lights were changing haphazardly simply because someone was late for work.

A huge thanks goes out to our emergency services around the Hudson Valley for responding to such a wide array of calls; check out some amazing local rescues below.