S3 6 Do Not Pass When Lights Are Flashing School Bus Sign K2 0083 W1 11 Hairpin Curve signs are W1 11 Hairpin Curve signs are essential for alerting motorists to an extremely sharp change in the horizontal alignment of the roadway Industrial Facilities & Mine Sites: Protect forklift crossings and heavy machinery routes by providing clear right of way signaling in loud or busy environments S3 6 Do Not Pass When Lights Are Flashing signs are essential for alerting motorists to the strict legal requirement to stop for a school bus that is loading or unloading passengers This clear and concise sign provides immediate awareness in areas with frequent school bus stops