QueueGuard

Warnings that move with the queue

T+00:00900 veh/h
EvaluationSite guidelineCode
Severe end-of-queue conflicts
(TTC ≤ 1 s or DRAC ≥ 3.4 m/s²)
0static0QueueGuard
Arrival speed at the queue
(85th percentile, km/h)
–static–QueueGuard
Queue time with no timely warning
(150–1500 m before the tail)
–static–QueueGuard
Throughput past the work zone
(veh/h — safety must not cost capacity)
–static–QueueGuard
Without QueueGuard

Static roadworks signs at fixed positions

same traffic, same drivers
With QueueGuard

Predicted tail · colour VMS chain · variable speed limits · alerts

Roadside devices what drivers see now (QueueGuard)

Speed0 → 100+ km/h eyes off road warned & alert braking severe conflict

Time–space diagram QueueGuard run · white = true tail, amber = estimated from detectors only, dotted = predicted +90 s

Alerts supervisor dashboard & worker phones

UHF CB 40No message drafted.