The ideal temperature for roasting vegetables is around 400-425°F. However, the temperature can be adjusted up or down depending on the type of vegetable and personal preference. It is important not to crowd the vegetables on the baking sheet and to spread them out in a single layer to allow for even cooking and browning. The estimated cooking time for roasting vegetables at 425°F is around 25-35 minutes. However, the cooking time can vary depending on the size and type of vegetable, so it is recommended to keep an eye on the vegetables and roast them until they are browned on the outside and tender on the inside.