They mark the edge of the safe area, keep clear of them.
In the UK red reflectors are always shown to the rear of a vehicle, never to the front, therefore they mean you are approaching the rear of car, lorry, bike etc.
You are going the wrong way on a road.
It means you are going the wrong way
RED!
RED!
Reflectors on the back of a costume, as well as on the heels and sides of sneakers, are the best places for reflectors on a costume. A car approaching the person in costume from behind then has more of a chance of seeing that person. For young children who are unaware of road rules, it is imperative to make them visible to all drivers.
get a police
Red
You are going the wrong way. White means correct direction, red means opposite direction (wrong way), blue means a fire hydrant near.
reflectors, on the lines on the edge of the road, always mean you are facing traffic the wrong way and could have a head-on collision.
on the wrong side of the road
Apparently you need some kind of reflectors on your plate. I was told this by a state trooper but received no ticket. I picked some up local for $1
Reflectors can be white, red, blue, green, yellow, or orange. There may be others as well.