what shape is the stop sign in highway code
Stop sign In the United States, stop signs have a size of 750 mm across opposite flats of the red octagon, with a 20 mm white border. The white uppercase letters in small caps forming the stop legend are 250 mm tall.[4][5] Larger signs of 900 mm (35 in) with 300 mm (12 in) legend and 25 mm (⅞ in) border are used on multi-lane expressways. Regulatory provisions exist for extra-large 1,200 mm (47 in) signs with 400 mm (16 in) legend and 30 mm (1 1⁄4 in) border for use where sign visibility or reaction distance are limited, and the smallest permissible stop sign size for general usage is 600 mm (24 in) with a 200 mm (7.9 in) legend and 15 mm (⅝ in) border.[6] The metric units specified in the US regulatory manuals are rounded approximations of US customary units, not exact conversions.[5][7] The field, legend, and border are all retroreflective. In the Vienna Convention on Road Signs and Signals of the UN, the instruction on the sign to stop is specified to be either in English as stop or written in the local language. Some countries use both. The sign's distinctive design was developed and first used in the US, and later adopted by other countries and by the UN. Despite this, the US is not a signatory to this UN Convention; the US has the same sign design as specified by the Convention, which adopted the US standard.
Yellow line (road marking) A yellow line (solid or dashed) indicates that crossing the line will place a driver in a lane where opposing traffic is coming at the driver. A double yellow line is a painted marking separating two lanes of a road. It consists of two parallel, solid yellow lines, and its presence usually indicates a no-passing restriction or no passing zone, where crossing the line is prohibited. Obvious exceptions to this no-passing restriction include emergency maneuvers or temporary traffic flow changes due to road work. Often the double yellow line has sections where one of the lines becomes dashed (in which case it is no longer a "double yellow"), indicating to the drivers traveling on the side closest to the dashed line that they may pass when it is safe. Double-yellow lines may be used to separate lanes of traffic traveling in opposite directions where passing would be dangerous, or to restrict access to lanes traveling in the same direction, such as HOV and express lanes on a highway.