Prepare the pasta according to package directions.
In a medium saucepan with a steamer basket, bring 1" of water to a boil. Place the broccoli and carrots in the basket, cover, reduce the heat to low, and steam for 4 to 5 minutes, or until tender-crisp. Transfer the broccoli and carrots to a colander and run under cold water to stop the cooking.
In a large bowl, toss the pasta with the broccoli and carrots. Add the tomato, scallions, Italian seasoning, and vinaigrette and toss well. Cover and refrigerate for at least 1 hour before serving.