Detour signs alert drivers to road closures or obstacles ahead and provide alternative routes to ensure road safety. The Federal Highway Administration sets standards, while the National Highway Traffic Safety Administration enforces compliance. State Departments of Transportation implement and maintain detour signs, which are manufactured and distributed by traffic sign companies. Construction companies coordinate with transportation agencies for sign placement. Educational institutions teach about detour sign standards, and first responders rely on them for navigation. Advocacy groups promote proper signage, while community groups help improve road conditions and advocate for signage. GPS navigation apps provide real-time detour information.