IMO the most important part of a simulation is the vehicles physics. The game vehicle should perform exactly as possible as real world performance(Handle,accelerate,braking...) Things like tire wear and temperature,setups, crash damage is added bonus. Qualifying and pitstops strategy is a 3rd step in making the game more racing feel. Arcade games focus on making a vehicle perform at a level that is higher than real life. Crashes, jumps and police chases are the popular setting for these games.