Preheat the oven to 400°. Divide the rutabagas, turnips and carrots between 2 large rimmed baking sheets. Drizzle 1 tablespoon of the oil over each sheet of vegetables and toss well. Spread the vegetables out in an even layer and season with salt and pepper. Roast until lightly browned and tender, about 40 minutes. Drizzle 1 tablespoon of the vinegar over each pan of vegetables and toss well. Roast until sizzling, about 3 minutes longer.