private static float getMaxArcCost(ZoneGeographique zone) {
        float maxArcCost = 0;
        for (Noeud noeud : zone.getNoeuds()) {
            for (Troncon troncon: noeud.getSortants()) {
                float cost = troncon.getCost();
                maxArcCost = cost > maxArcCost ? cost : maxArcCost;
            }
        }
        return maxArcCost;
    }