From planning objectives to network alternatives

In one sentence

Objectives in, alternatives out — the engineer decides what goes forward.

Why it matters

The planner writes the brief on the map: which LRT stations to connect, which corridor to protect, maximum route length, minimum coverage, no parallel running, a fleet limit. The generator proposes candidate networks; twenty routes are generated, the planner removes and moves routes, ten are retained, local requirements add thirteen more — a 23-route engineered variant that is then simulated and compared. Not "AI designs the network".

Most of what a transit planner does before a model run — drawing, scheduling, checking reach and cost — is where time is lost between the big model iterations. Seeing that step on a map, with the numbers following the sketch, is what makes the workflow believable.

Sources

• Objectives and constraints are typical of a network-redesign brief (illustrative)
• Schematic, synthetic city (not a real network or tile map); values are illustrative

What you see

1. 00.7The brief on the map
2. 05.0Generate
3. 06.8Three candidates
4. 11.320 generated
5. 12.6Planner removes routes → 10 retained
6. 15.8Local requirements → 23 routes
7. 19.4Simulate & compare

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