Zombie Derby
25 Achievements
4,000
0-2h
Xbox One
Xbox Series
Racer
Accelerate to 100 km/h
100
85.63%
How to unlock the Racer achievement in Zombie Derby - Definitive Guide
brummiechris
TrueAchievements
TrueAchievements
This unlocked for me once to I was able buy the second vehicle (hunter pick-up truck).
This is only available to purchase after completion of both levels Tutorial level and Level 1.
I upgraded the Nitro, 1 lvl and Engine, 2 lvl. It was then a matter of startingLevel 2 and holding down accelerate
and Nitro boost 
and the achievement popped. You will require coins/points to unlock these upgrades but by the time you get to Level 2 you will have replayed Level 1 enough that you should easily be able to afford this
This is only available to purchase after completion of both levels Tutorial level and Level 1.
I upgraded the Nitro, 1 lvl and Engine, 2 lvl. It was then a matter of startingLevel 2 and holding down accelerate
and Nitro boost and the achievement popped. You will require coins/points to unlock these upgrades but by the time you get to Level 2 you will have replayed Level 1 enough that you should easily be able to afford this