Here is the full list of all 47 Pixel Traffic: Highway Racing achievements.
Unlock Racing Supercharged car
Unlock all cars
Unlock Racing car
Unlock Racing Plus car
Unlock Green Super Mini car
Unlock Super Mini car
Unlock Super Mini Sport car
Unlock Offroad Supercharged car
Unlock Offroad car
Unlock Offroad Tuning car
Unlock Muscle Tuning car
Unlock Muscle car
Unlock Muscle Super car
Unlock Cruiser Plus car
Unlock Cruiser car
Unlock Pink Cruiser car
Unlock Mini Sport Tuning car
Save 1000 coins
Save 500 coins
Save 300 coins
Save 200 coins
Unlock Mini Sport car
Unlock Heavy Tank
Score 300 points
Unlock Battle Tank
Unlock Tank
Unlock Pink Mini car
Unlock Mini car
Unlock Police car
Score 250 points
Score 200 points
Score 150 points
Drive over 150 km/h for 3 seconds
Drive over 200 km/h for 3 seconds
Drive over 250 km/h for 3 seconds
Drive over 300 km/h for 3 seconds
Drive over 320 km/h for 3 seconds
Drive over 100 km/h for 3 seconds
Unlock Coupe Tuning car
Unlock Coupe Plus car
Save 100 coins
Score 100 points
Save 50 coins
Crash your car
Score 50 points
Score 25 points