Here is the full list of all 28 On The Road - there are Truck Simulator achievements.
Hire six drivers for your company
Reach Level 7
Buy a semi trailer
Own five trucks and five trailers
Hire three drivers for your company
Buy a drawbar trailer
Buy a gigaliner roadtrain combination
Own three motor vehicles
Combine enough assignments to reach 90% of your vehicles maximum payload
Buy a tandem trailer
Own two motor vehicles and two trailers
Combine enough assignments to reach 70% of your vehicles maximum payload
Hire the first driver for your company
Combine enough assignments to reach 50% of your vehicles maximum payload
Get caught by speed camera
Create a second savegame
Reach Level 3
Deliver an assignment without any damage
Reach Level 1
Entirely fill your tanks.
Reach Level 10
Own nine trucks and nine trailers
Own one motor vehicle with a mileage of at least 10k kilometres.
Own one motor vehicle with a mileage of at least 100k kilometres.
Own one motor vehicle with a mileage of at least 500k kilometres.
Deliver an assignment with max 10% damage
Deliver an assignment with max 50% damage
Deliver an assignment with full damage.