The one-junction traffic challenge.
The ITMS requirement was specific: when a camera flags congestion at a junction, show the operator that junction's feed. Reviewing it myself, the way I work through anything I design, one question kept surfacing: what happens after the operator sees the jam and turns the signal green? If the next junction is already backed up, turning this one green clears nothing; it pushes the congestion one junction forward.
So a single junction's feed was the wrong unit. The fix was a corridor view: when an alert opens, the system shows five junctions in context automatically, the triggered one, two ahead, two behind, so the operator sees the consequence of an action before taking it. Parallel and intersecting roads stay one click away on the map but do not auto-open: enough context to make a system-level decision, not so much that the decision gets harder. For VIP convoys and emergency vehicles, the same corridor follows the pre-configured route.
Every nearby camera could have opened on the alert. Showing them all would have buried the operator. Choosing exactly five, the triggered junction and two each side, was the design judgment: enough to see the whole corridor, little enough to still decide.