GLOSA sounds simple on a whiteboard: read the countdown, recommend a speed. In production it is a real-time systems problem involving unreliable radio links, probabilistic timing, and hard deadlines shared with safety-relevant control loops.
Field deployments show RSU coverage dropping out behind trucks, foliage, and building overhangs. The decoder tracks a per-intersection freshness timer and falls back to dead-reckoned countdown extrapolation for up to 600 milliseconds before withdrawing the advisory entirely, preventing stale speed recommendations from lingering on the driver display.
Because different RSU vendors ship firmware with subtle interpretation quirks around optional ASN.1 fields, the decoder is validated against a growing regression corpus of packet captures gathered from production intersections, catching vendor-specific malformations before they ever reach a vehicle in the field.