This is a pretty easy and quick achievement to obtain. All you need to dois create and save 10 custom routes.
1) When on the main menu press "START".
2) Navigate on over to "Playtime".
3) Select "Route Creator" from the bottom.
4) Select "Create A New Route".
5) Choose a city to create the route in.
6) Start the route editor by pressing "A" on the black and white chequered flag.
7) Now select one of the yellow round icons that appear.
8) Continue to select different yellow icons until a yellow and black chequered flag appears.
9) Now click the black and yellow flag to finish the track.
10) Now all you need to do is press "A" to "Accept and Save" the route.
11) Give the route a name or use the one that pops up.
12) Now repeat this 9 more times.