A cruise server as a lfs setting means no "racing" and anyone can drive either way, as a server they are usualy servers where you cruise around any direction rather than race, there are barriers & tyres to creatle "lanes" around a track and then use coding and cleverness behind the scenes to place speed limits in certain areas, you get $ in that server for driving every km and you start off with a crappy car say uf1 and then as you get $ you can 'buy' more cars,
There are also people that drive as offical police in the faster cars and pull you over when you speed and make you pay fines. all sorts of other things happen and they are all different from server to server.