I finish this beast today, this achievements drive me nuts!!!
My tip is, control your aceleration and never breaks, just take your finger off the aceleration a little for pass the traffic, and memorize the colors of your oponents, blues and reds come from left, and all others come to right and middle, so, aways try pass on the right side of the track, take care on the desert passages, i considered the most hard parts of this achievement, in the desert segment, the corners are all thight, so, take off the finger on the acceleration and try dont go out the track, is vital for cross the checkpoint.
Here my video, i hope this all helps you guys, keep try and focus and memorize the most hard sectors, is hard, but not impossible, prepare to be angry!!!