How far behind a disabled vehicle should flares or reflectorized devices be placed on a highway?

Flares or reflectorized devices should be placed 30 meters behind a disabled vehicle on a highway to ensure adequate warning for oncoming traffic. This distance is significant because it allows approaching drivers enough time to react safely to the hazard on the road. By positioning the warning signals well back from the vehicle, it creates a visual alert well in advance of the obstruction, which is especially important in high-speed environments like highways. This helps to prevent accidents by providing ample notice to other motorists that there is a disabled vehicle ahead and that they may need to maneuver or slow down.