

There is usually some guidance, although the regulations are usually written with more wiggle room than structural standards because of varying site conditions.
However, the hill causing an increase to the speed of the car and that the area has a known pedestrian draw to it would tip the scales more towards installing a stop sign.



Only one oil country switched to Euros and an invasion switched it back to dollars.
A lot of the international banking structure was built on American systems of banking, so the dollar got baked into a lot.
Until Trump, the dollar was generally seen as more stable given its longevity and being the currency of the largest superpower.
Also, compared to the Euro and Yuan, the American dollar has an internal hedge when it comes to energy prices given that the USA can supply most of its energy needs by itself. It is hard to handle an oil shock when the currency’s value drops because the internal market can’t afford oil.