They can probably mean different things in different states. In my area they mark the location of roadside fire hydrants.
Blue reflectors on the road typically indicate the location of a fire hydrant or a nearby water source for firefighters to use in case of emergencies. They help emergency responders quickly locate these resources, especially during nighttime or low visibility conditions.
You are going the wrong way on a road.
Blue reflectors are typically used in some regions to indicate the presence of emergency services or to mark specific features on roads. However, their legality can vary by location, as traffic laws differ between states and countries. It's important to consult local traffic regulations to determine the legality of blue reflectors in a specific area. In many places, unauthorized use of blue reflectors by civilians is prohibited.
Some names for specific types of raised pavement markers include Botts' dots, delineators, cat's eyes, road studs, or road turtles. Sometimes they are simply referred to as reflectors.
The average road reflectors in America are orange. Orange is the standard color b/c it is bright and can be highly reflective. Also, the color orange usually stands out on roads.
Catseye's are reflectors that sit in the middle of the road and light up at night.
Known as cats eyes Invented by Yorkshire man Percy Shaw
To see the road at night.
on the wrong side of the road
You are going the wrong way. White means correct direction, red means opposite direction (wrong way), blue means a fire hydrant near.
If the bicycle is road legal(has brakes, lights, reflectors) - sure.
Street reflectors enhance road safety by improving visibility, especially at night or during low-light conditions. They guide motorists by marking lane boundaries, intersections, and hazards, helping drivers maintain proper alignment on the road. Reflectors also aid in reducing accidents by making road signs and other important features more noticeable. Overall, they contribute to safer driving experiences by providing clear visual cues.