"Set distance" refers to establishing a fixed space or measurement between two points or objects that should not be changed. It means deciding on a specific and unchanging separation or gap. Full definition
This next - generation cruise control uses radar to set the distance between you and the vehicle ahead of you. (canadianbusiness.com)
Adaptive cruise control maintains a pre set distance behind the car ahead of you, simplifying highway driving and enhancing safety. (sloanetoyotaphiladelphia.com)
Users set their distance and age parameters and start viewing matches. (cyberdatingexpert.com)