Heat oven to 425 degrees. Spray a large baking pan or two if one won't be big enough, with vegetable spray and set aside. The vegetables need to be spaced out enough so that they are in one layer. This will allow all of the veggies to brown evenly. Using a large bowl, add in all of the veggies that have been chopped. In a small bowl combine the olive oil, balsamic vinegar, garlic, Italian seasoning, salt and pepper. Whisk to mix well. Drizzle the dressing evenly over the vegetables. Toss with a large spoon to evenly coat the veggies with the dressing. Transfer the vegetables to the prepared baking pan(s). Place in oven and roast for 20-30 minutes. I like the veggies to be a little on the under cooked side so I take them out earlier rather than later. If you prefer them to be a little softer, then you will need to increase the roasting time. It is very important to remove the veggies from the oven periodically while roasting and toss them so that one side doesn't get too roasted and the other side not enough.