EDIT: As chiokjarse pointed out. This is not a story mission but rather a side mission that CAN be played, but could be omitted as well. So you could argue that it could be seen as missable. However, I think that this game will give you the oppotunity to walk through Gotham and do stuff, even if you have finished the story. Therefore, I will keep the description of this achievement as unmissable below, until someone can confirm for sure that it is in fact missable.
---------------------------------------------------------------------------------------------------------------------------- This achievement is unmissable.
*** Spoiler - click to reveal ***You will get this pretty early in the game after you have dropped Poison Ivy in the GCPD. Talk to Jim Gordon before leaving, and the Riddler quest will become available in the menu. Select it in the menu and drive to the marker on the minimap.
Take you Batmobil with you because you will need it for this trial. For the trial to be finished, you need to finish a race track 3 times in a row. Every time you will have less and less time and the track will alter slightly. Keep pushing whenevery you need to change the track to your advantage. The 3 lap will be the hardest, but with pushing the button and some luck you will easily get it.
EDIT: capnjiffy pointed out that you do not have to push to change the track. You can also use instead. Use whatever button you find more convenient ;-)
If you need additional help, refer to the video below:
(video credit: PS4Trophies)
Hope this helps you guys!
Any improvements? Let me know in the comments below!