Quebec City's tourist area is really compact. You should not use your car if your hotel is in the same area. You can walk to every attraction in town.
You may want to use your car to go to Montmorency falls and Ile d"Orleans, outside of town.
Traffic is not very bad in Québec City, the trickiest part might only be crossing the bridges over St-Lawrence River at the beginning and end of business days. If your are staying outside downtown, you can easily pay for a parking in the area for the day and walk around to visit Old Québec, Old Port, Petit-Champlain and most parts of the city center. Walking is definitely the best way to discover the city!
Here are many convenient parking adresses in downtown Québec City:
Visiting Montmorency Falls Park and Île d'Orléans with your car is aso a great idea! You could also travel to Canyon Sainte-Anne and Cap Tourmente National Wildlife Area wich is beautiful at this time of the year. If you are a fan of hiking, we recommend you also consider driving to Jacques-Cartier National Park in the North of our region!
Uber was great way to get around. Just liad the app. Car good for day trip to Ile de Orleans