To unlock the achievement, you must "Complete" a level with a score of 0. That means that you need to finish the level countdown while preventing any cars from getting to their flag. The main challenge in this is preventing a traffic jam, where no cars from a entry lane are moving and a yellow caution symbol fills up, ending the game.

To complete this challenge, you first want to choose a map (I recommend Offset), then connect the entry roads to the exit roads.

Then place traffic lights at each entry lane and 1 tile in front of.



This will allow you to limit the number of cars that enter the playing area.



Once you have placed all the traffic lights, use your remaining money to make it the longest road to the end as possible, placing a traffic light at the end.



Now to program the traffic lights, keep the one at the end on red for all 12 phases.



Program all traffic lights at the mouth of the entry lane to 1 green 2 red repeating.



Program all traffic lights in front of the entry traffic light as an opposite with 1 red and 2 green repeating.



That's it, your done! Press play and the programmed traffic lights + long road + all red light at the end should last you until the timer goes down, winning you the achievement.



If you are struggling, you can copy paste this into the level: