The present invention extends to methods, systems, and computer program products for using geofences to restrict vehicle operation. Aspects of the invention include creating dynamic geofences and limiting vehicle movements (e.g., speed, acceleration, steering, etc.) within and in the vicinity of the dynamic geofences to protect pedestrians from physical harm. In general, radio devices track people in an area by counting the number of devices and calculating the number of people based on average number of devices per person. Using count and location data, a geofence is created when population or population density within an area exceeds a threshold. The geofence can be sent to vehicles to restrict vehicle operation, for example, slowing down or stopping the vehicle, within and around the geofence.