Answer: Parking brakes are an essential for safety. Parking brakes are used more in manual transmission vehicles than in automatic transmission vehicles. Every time the vehicle is parked, the parking brake is engaged to keep the vehicle from rolling away. It is also imperative to have a fully-functional parking brake in the case of an emergency or if your vehicle’s regular hydraulic brakes completely fail. Parking brakes are rarely used in an automatic transmission vehicle. However, unused parking brakes can lead to rusted/corroded cables and, eventually, an inoperable parking brake. That is why it is important to use the parking brake when you park your vehicle, especially on hills, to keep the parking brake’s cables in good condition.