Place an oven rack in the center of the oven and preheat to 375 degrees F. Coat a large rimmed baking sheet with nonstick vegetable oil spray. Combine all the vegetables in a large bowl. Drizzle with oil and sprinkle with rosemary, salt and pepper. Toss to coat. Spread out vegetables in a single layer on the prepared sheet. Roast for 25 minutes until tender.
Bring a large pot of salted water to a boil over high heat. Add the pasta and cook until tender but still firm to the bite, stirring occasionally, about 8 to 10 minutes. Drain and place in a large serving bowl.
In a medium bowl, whisk together the sour cream, safflower oil, buttermilk, lemon juice, lemon zest, chives, mint, parsley, salt, and pepper until smooth.
Add the roasted vegetables and dressing to the cooked pasta. Toss until all ingredients are coated and serve.