An apparatus and method for generating incursion alerts in response to incursion events detected by incursion detector units, attached to safety icons such as traffic cones and signage. The incursion detector units are activated by automatic activation sensors and remain activated for a period of time. Alerts are generated in response to impacts detected at the safety icons by an incursion detector and transmitted to one or more incursion receiver units which annunciate the alert with audio, lights, or tactile output to warn personnel of possibly impending danger. Alert signals are preferably repeated by other incursion detectors wherein the distance and conditions over which the alert signals may be communicated is extended. A validation circuit and tilt sensor filter out not incursion events such as wind tipping. The incursion detectors may generate area alerts, or personal alerts and can transmit operational status and alerts to discrete groups of receivers.