For this achievement, you will first need to find a Ford SVT Raptor (view the video for a location). Once in the car, you will need to start a police chase by hitting a police car or speeding by one. Once this starts, take your time to ram police cars off the road to score takedowns and bust through roadblocks to get extra takedowns. Once you take down 10 cops in 1 pursuit, the achievement will unlock. You can now try to escape the pursuit, although it may be quite difficult.
View the video: