Drawing on the sources, reflective gear plays a significant role in saving the lives and reducing injuries for pedestrians and cyclists, particularly in low-light conditions. Vulnerable road users face substantially elevated risks at night, with fatalities up to seven times more common than during the day. Reduced visibility is a primary factor in these crashes, often more so than driver impairment.

Retro-reflective materials return light back towards the source, like vehicle headlights, making wearers highly visible in darkness. Fluorescent materials are effective for daytime and twilight, absorbing UV light and re-emitting it to appear brighter.

This technology translates to dramatically increased detection distances. A pedestrian without a reflector might be visible from only about 50 meters at night, while one with a reflector can be seen from roughly 350 meters. Placing reflective material on moving limbs (ankles, knees, wrists) leverages the "biomotion" effect, helping drivers recognize a human presence faster and from greater distances. Biomotion can increase pedestrian recognition distance by up to three times compared to a standard reflective vest and detection distance by up to ten times. For cyclists, biomotion patterns can increase visibility by as much as six times compared to no reflectors.

The most compelling evidence comes from real-world outcomes in regions with mandatory use. Several European countries requiring pedestrians to wear reflectors have reported significant reductions in fatalities, ranging from 30% to 75%. Poland saw pedestrian fatalities decrease by 33-37% after mandating reflectors in 2009. The Czech Republic reported a 33% reduction after its mandate in 2015. Estonia, with mandates since the 1990s, reported a remarkable 75% drop in pedestrian fatalities. Studies on cyclists have also shown safety benefits, with some reporting lower accident rates for those using high-visibility clothing.

However, a recent study by the IIHS indicated a new challenge: some Pedestrian Automatic Emergency Braking (AEB) systems might be "confounded" by certain reflective materials, potentially making pedestrians less detectable to the vehicle's sensors. In one test, some vehicles failed to slow down for dummies wearing biomotion-configured reflective strips. This is a "worrisome blind spot" that highlights the need for vehicle technology to adapt and does not negate the established benefits of reflective gear for enhancing visibility to human drivers.

Factors such as choosing the correct material for conditions (fluorescent for day, retro-reflective for night), proper placement (emphasizing biomotion), and environmental variables are important for effectiveness. Despite human factors like low user acceptance or overestimating personal visibility, the significant fatality reductions in countries with mandates underscore that reflective gear is a powerful and proven intervention that saves lives.