Ahhh, a "throttle lock" suggests a system in which the engine speed is set at a constant speed for extended periods of time. I've only ever experienced this when flying airplanes and driving farm tractors. Typical cars and trucks are only equipped with foot operated gas pedals requiring...
Sorry, Crissa, I must be missing something. For the 60+ years I've been driving 'gas pedal' cars, I also had to keep my foot on the gas pedal and regulate the speed by constantly adjusting my foot pressure on the pedal. Not exactly 'relaxing' in my experience. Tens of thousands of miles now...