The car you passed will always catch up with you thanks to 'Friday the 13th' rule

Embargoed until: Publicly released: 2026-04-01 10:01

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You overtake a car on the road, thinking you got away from it, but in the next moment, it's sitting right behind you at the lights. It's like a scene from a slasher film, or at least that's what Irish researchers have devised, by basing this phenomenon on cult horror monster Jason Voorhees from the Friday the 13th series. Their research looked at how, despite overtaking a car, you can get caught by the timing of the red-lights, which erases small advantages in your speed and gives the slower car time to catch up to you again and again. Named the The Voorhees Law of Traffic, the team say the effect isn't horror, but instead is statistics at work in your everyday driving.

News release

From: The Royal Society

The Voorhees Law of Traffic: A Stochastic Model Explaining Why the Car You Passed Always Returns

Why does the car you just overtook always seem to reappear at the next red light, like Jason Voorhees in Friday the 13th? In the films, Jason never seems to hurry, yet he inevitably shows up right behind his fleeing victims. This study suggests traffic can work the same way. A simple mathematical model shows how red-light timing can erase small speed advantages, allowing a slower car to catch up again and again. Across multiple intersections, these probabilities compound, creating an almost supernatural feeling of inevitability. The effect isn’t horror, it’s statistics at work in everyday driving.

Researchers may have worked out why the car you just overtook always seems to reappear at the next red light. A mathematical model shows how red-light timing can erase small speed advantages, allowing a slower car to catch up again and again. Across multiple intersections, these probabilities compound, creating an almost supernatural feeling of inevitability. The effect isn’t horror, it’s statistics at work in everyday driving

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Journal/
conference: Royal Society Open Science

Research:Paper

Organisation/s: Dublin City University, Ireland

Funder: No funding has been received for this article.

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