In Act 4 of Episode 3 on the Villain side (The Lure of the Night), you will build a robot close to the end of the stage. When you reach the end, you will be besieged by three big transport vans that release police officers. Before you smash all three (when their doors are open), stomp around and destroy all the other smaller police vehicles.
The Achievement does not include the three transport vans in its count, so keep searching for more in the immediate area if the Achievement hasn't popped yet. Once it unlocks, you can smash the final transport and complete the level.