Preheat oven to 425 degrees. Spray large roasting pan with nonstick cooking spray.
Place potatoes in prepared pan. Drizzle with 2 tablespoons oil; toss to coat evenly. Roast 10 minutes.
Add bell peppers and onion to pan. Drizzle with remaining 1 1/2 tsp oil. Sprinkle with garlic, salt and black pepper; toss to coat evenly.
Roast 18 to 20 minutes or until vegetables are browned and tender, stiffing once.
Transfer vegetables to large service dish. Drizzle with vinegar; toss to coat evenly. Add basil; toss again. Serve warm or at room temperature.