Road Signs By Ladwa Safety Solutions Pvt. Ltd.

The earliest road signs were milestones, giving distance or direction; for example, the Romans erected stone columns throughout their empire giving the distance to Rome. In the Middle Ages, multidirectional signs at intersections became common, giving directions to cities and towns.
The first modern roadsigns erected on a wide scale were designed for riders of high or 'ordinary' bicycles in the late 1870s and early 1880s. These machines were fast, silent and their nature made them difficult to control, moreover their riders travelled considerable distances and often prefered to tour on unfamiliar roads. For such riders, cycling organisations began to erect signs that warned of potential hazards ahead (particularly steep hills), rather than merely giving distance or directions to places, thereby contributing the sign type that defines 'modern' traffic signs.

Color schemes
The North American, Australian and New Zealand colours normally have these meanings:
red with white for stop signs, yield, and forbidden actions (such as No Parking) green with white letters for informational signs, such as directions, distances, and places brown with white for signs to parks, historic sites, ski areas, forests, and campgrounds blue with white for rest areas, food, gasoline or petrol, hospitals, lodging, and other services black with white for commercial.