Jev runs a city’s traffic

# Jev Traffic Sim

An interactive Chicago traffic simulator that runs **one experiment**:

> Same scenario. Same trip. Same driver. **Different city intelligence.**

You watch a single car cross real Chicago geography while the whole city simulates around
it, and the same scenario is also played out by two deterministic baselines. The payoff is
the comparison, not a scoreboard.

**Live:** deploy URL is published with the release notes.

## The experiment

| Column | What it is |
| --- | --- |
| **Fixed** | Signals on a fixed rotation. No sensing, no adaptation. The do-nothing baseline. |
| **Adaptive** | Signals that react to local queue pressure and waits, with the same min/max green, yellow, all-red and starvation protection as everything else. |
| **Jev** | A citywide policy from an external evaluation model (TypeSafe AI's `jev` through the Vercel AI Gateway). It sees ONLY citywide traffic state and answers bounded, typed questions; its answer becomes corridor/region weights and a small pressure modifier. |

The visible run is **Jev**. Fixed and Adaptive play the *same* scenario headlessly, in a
worker of their own, so the trip you are watching never stalls.

**Nothing about the driver changes the scenario.** Tourist and Local are two ways of driving
the same trip in the same city: the tourist follows the shortest route and sits through
queues; the local knows the network and reroutes around trouble. Pick a driver, then compare
controllers under that driver.

## Same-scenario fairness

A comparison is only shown when it is honest:

- all three runs share one **scenario fingerprint** — the scenario (trip, traffic level,
  driver, seed, horizon) is hashed into a short id, and results with different ids are never
  put side by side;
- all three runs are built from one *