Here is the full list of all 21 Autobahn Police Simulator 2 achievements.
Arrest the truck driver
Buy all upgrades
Buy all upgrades in GARAGE
Complete 5 car chases successfully
Buy all upgrades in TRAINING
Buy all upgrades in STATION
Gain 50,000 Influence Points
Unlock and finish Konrad's mission
Arrest the mastermind behind the smuggler ring
Finish the campaign
Find all 20 rubber duckies
Interrupt the big drug deal and catch the dealers
Find and arrest the stone thrower
Discover all 10 memorials in the world
Unlock all Fast Travel Stations in the world
Enjoy a donut in all 5 donut shops
Show mercy with the truck driver and let him go
Finish an accident 100% completely
Drive at least for 10 seconds 200 kph or more
Join the autobahn police
Finish a traffic control 100% completely