func chooseAcceleration(racer: Player, track: Track, opponents: [Player]) -> GridVector {
    var bestScore = Int.min
    var bestAccel = GridVector(0, 0)

    for acceleration in allAccelerations {
        let newPos = racer.position + racer.velocity + acceleration
        let newVel = racer.velocity + acceleration

        if wouldCrash(from: racer.position, to: newPos, track: track) {
            score = -1000
        } else {
            score = progressTowardFinish(newPos, track.finishLine)
            score -= distanceToTrackCenter(newPos, track) * 0.1
            score -= speed(newVel) * 0.05  // Prefer control
        }

        if score > bestScore {
            bestScore = score
            bestAccel = acceleration
        }
    }
    return bestAccel
}