When you need help, emergency personnel can reach you more quickly if your address numbers are plainly visible from the street. Address numbers clearly posted on a house can save police, fire and emergency medical personnel time in responding to urgent calls. House numbers should be clearly visible day or night from the street. Numbers should ideally be six inches high posted on a contrasting colored background and preferably made of reflective material. Block letters are easier to read than script letters. House numbers should also be placed at the driveway entrance and on your mailbox if the house is some distance from the street.