Road junction

Roads began as a means of linking locations of interest: towns, forts and geographic features such as river fords.

In the United Kingdom and other countries, the practice of giving names to junctions emerged, to help travellers find their way.

This was followed by specialized junction designs that incorporated information about traffic volumes, speeds, driver intent and many other factors.

[3] Non-signalized designs include the cloverleaf, contraflow left, dogbone (restricted dumbbell), double crossover merging,[2][4][5] dumbbell (grade-separated bowtie), echelon, free-flow interchange, partial cloverleaf, raindrop, single and double roundabouts (grade-separated roundabout), single-point urban, stack, and windmill.

Signalized designs include advanced stop line, bowtie, box junction, continuous-flow intersection,[6] continuous Green-T, double-wide, hook turn, jughandle, median u-turn, Michigan left, paired, quadrant, seagulls, slip lane, split, staggered, superstreet, Texas T, Texas U-turn and turnarounds.

[3] Non-signalized designs include unsignalized variations on continuous-flow 3 and 4-leg, median u-turn and superstreet, along with Maryland T/J, roundabout and traffic circle.

[7] It has been considered that several causes might lead to fatalities; for instance:[7] A number of features make this protected intersection much safer.

This design places a circulatory cycle track around the edge of the junction, with pedestrian crossing on the inside.

Pedestrian aids include crosswalks, pedestrian-directed traffic signals ("walk light") and over/underpasses.