Date: 1871 a customary practice (as driving always on a particular side of the road or yielding the right of way) developed in the interest of safety and often subsequently reinforced by law
RULE OF THE ROAD
Meaning of RULE OF THE ROAD in English
Merriam Webster. Explanatory English dictionary Merriam Webster. Толковый словарь английского языка Мерриам-Уэбстер. 2012