step 1) drive bus

step 2) turn bus

step 3) stop bus in the green rectangle

step 4) press space bar while in the green rectangle and wait 5 seconds for the level to finish

step 5) repeat 5 times and go back to menu to check if the level 5 bus is unlocked

step 6) complete the game in frustration because you didn't get the level 5 bus

step 7) congratulations! you can now free roam in a bus