The hardest emergency to dispatch for is a victim who is moving — being driven somewhere in a vehicle. A static alert radius is useless: by the time responders see it, the victim has left it. Guardian's answer is to stop chasing and start predicting.
First, be sure they are actually moving
A motion classifier watches two independent speed sources with hysteresis. A single GPS glitch — the kind that teleports a phone 300 metres for one reading — is discarded, so dispatch never flip-flops between modes. Only when the victim is genuinely travelling at 40 km/h or more does moving dispatch take over.
An anchor planted 1 km ahead
Guardian projects the vehicle's path and plants an anchor one kilometre ahead of it. Around that anchor it builds a cluster of four overlapping alert zones with a bridge circle at the seam — coverage the vehicle is about to drive through, not coverage it has already left. Responders inside receive zone-entry alerts before the vehicle even arrives.
Bridges, drift and expansion
Order-normalised bridge keys stitch the four zones into a single corridor, so a vehicle weaving between zones never falls into a gap. If it drifts off the corridor entirely, a bridge-drift re-ring covers the gap — with the same per-alert deduplication used everywhere in Guardian, so nobody is pinged twice. Any zone that goes unanswered for 90 seconds expands by 5 km.
Re-anchor, and dismantle
If the vehicle exits the cluster, Guardian re-anchors a fresh one further ahead. And when the vehicle finally stops, stop-detection dismantles the cluster and hands dispatch back to the stationary expanding-ring strategy. One more detail matters: the responder's map uses byte-for-byte the same destination-point formula as the server — responders see exactly what dispatch is computing.