I had them in the middle of my oven (which is a larger oven, almost double the width of most ovens) on 190 C fan forced. (dessertfortwo.com)
When that sheet pan full of vegetables hits the super-heated oven floor — which, in most ovens, is where all of the heat comes from — they get an immediate hard sear which jump - starts the caramelization process, much as they would in a pre-heated sauté pan. (bonappetit.com)