The brightness of reflective bands depends on several factors. One of the main causes of the insufficient brightness is the quality of the reflective material used in making the band. If the material is of low quality, the reflective effect will be poor, and it won't be visible at night or in low-light conditions.

In conclusion, by using high-quality materials, placing the reflective band correctly, and keeping it clean, we can ensure the brightness of reflective bands is sufficient, thus increasing safety for pedestrians, cyclists, and drivers. Let's adopt safe practices and make the world a safer place.