BAJA Edge of Control

I would advise doing this after the completion of your Baja Career and after you race your choice of BAJA 250/500/1000 events. When those are completed, from the Main Menu go to Race > Circuit Race and then choose Uyuni Salt Flats. Complete all these tracks, setting both the AI and laps to 5. You can set the AI difficulty to 70% (the easiest) and use a Trophy Truck to race all of the races, as they are the fastest. After completing all of the Circuit Races, if the achievement doesn't unlock, you might have to race the rally races associated with this location. If this is the case, go to Race > Rally Race. The three associated rally races are Lonesome Dove Rally, Split Rock Rally, and Uyuni Salt Flats Rally.

choose race , circuit race , choose uyuni salt flats ,after completing the career you only need to complete bloody basin,dead wash,tarantula glucth,lone wolf canyon,sundance peak,scorpion ridge,iron king trail and still water. there's no need to complete the rest of the circuit race and rally , my cheevo pop after my still water race. :)