Most rides use relatively simple mechanical means for locking lap bars and shoulder bars in place. Some rides use a combination of mechanical and hydraulic systems, and the most recent systems generally use hydraulic locking systems.

Rollercoaster restraints typically use one of two primary locking mechanisms: ratcheting bars or hydraulic cylinders. Ratcheting restraints use a "pawl and gear" system that allows the bar to move down in small increments but prevents it from moving up unless a manual or solenoid-activated release is triggered in the station. This is why you hear a "clicking" sound as you pull the bar down. Hydraulic restraints use a piston filled with oil; when the restraint is closed, a valve locks the oil in place, preventing the piston from moving in either direction. This allows for an "infinite" number of positions, making them more comfortable for diverse body types. Both systems are designed with a "fail-secure" philosophy, meaning they require power to unlock but will remain locked even if the ride loses all electrical power. In 2026, many modern coasters also include secondary electronic sensors that transmit a "restraint closed" signal to the ride's computer (PLC), preventing the train from leaving the station unless every single seat is confirmed as safely locked.