<P> 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 . Larger signs of 900 mm ( 35 in ) with 300 mm ( 12 in ) legend and 25 mm ( 7⁄8 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 ⁄ 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 ( 5⁄8 in ) border . The metric units specified in the US regulatory manuals are rounded approximations of US customary units , not exact conversions . 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 . </P>
<P> 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 . Larger signs of 900 mm ( 35 in ) with 300 mm ( 12 in ) legend and 25 mm ( 7⁄8 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 ⁄ 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 ( 5⁄8 in ) border . The metric units specified in the US regulatory manuals are rounded approximations of US customary units , not exact conversions . 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 . </P>
what are the measurements of a stop sign
what are the measurements of a stop sign
a size of 750 mm across opposite flats of the red octagon
a size of 750 mm across opposite flats of the red octagon