The Complete Handbook of Emergency Road Flares

Chapter 1: Understanding Emergency Road Flares

You are stopped on the right shoulder of an interstate at 2:00 a.m. A tractor-trailer passes you every four seconds, each one displacing enough air to rock your vehicle and generating a sound that you feel more than hear. Your vehicle is dead, or at least not driveable. It is dark, there is no street lighting, and the next aid is maybe two exits away or maybe twenty. The only thing between you and becoming an afterthought in a crash report is the plastic case in your trunk that you have probably ignored since the day you bought the car. This is what an emergency road flare is for.

An emergency road flare is a device that produces a high-intensity signal, generally red or orange, intended to alert approaching motorists to the presence of a stationary vehicle, a hazard, or a person in or near the roadway. That is the entire job. It is not a toy, not a convenience item, and not a cosmetic accessory. It is a one-of-a-kind safety tool with a narrow, life-saving purpose, and it has to function on the worst day of someone's year when they are least prepared to think clearly. Understanding the technology, the physics, and the application of these devices is critical for anyone who spends time on the road professionally, which is why this chapter exists.

There are three primary ways to generate that warning signal. The classic version is the pyrotechnic flare, often called