Cut potatoes, bell pepper, and onion to even bite-sized pieces. In a large bowl, combine potatoes, bell pepper, onion and carrots. Toss with olive oil and seasonings (parsley, thyme, garlic powder, salt and pepper) until vegetables are evenly coated.
Spread vegetable mixture onto large sheet pan in a single layer. Roast in preheated oven at 400°F for 20 minutes. Remove from heat.
Toss zucchini with a dash of olive oil, and add to top of sheet pan. You can stir/flip vegetables at this point. Roast for and additional 15-20 minutes or until desired level of tenderness is reached.