Police Simulator: Patrol Officers

This is easiest done through two methods:

1. reporting to an incident: when a request comes through to respond to an incident, accept a request on the d-pad and head to the location marked with a red blip on your compass (a guide line should appear on your GPS map as well if you have a car).

When you arrive, all the drivers will be standing next to their cars involved in the accident.

Proceed to Testing and arresting below.

2. Requires access to patrol vehicle - Stopping a vehicle for an infraction: whilst roaming, a yellow arrow will appear above NPC cars, and you should get a notification top centre of your screen (e.g. This vehicle ran a red light).

Position your patrol vehicle behind them and press to flicker your police lights at them to pull them over.

They should pull over. Exit your vehicle and approach the driver's window and interact with them.

Tell the NPC to exit their vehicle, so you can proceed to the Testing and arresting section below.

Testing and arresting:

Interact with the driver, access the DUI Tests tab in the menu and test for either/both Alcohol or Narcotics.

If the test for alcohol returns 0.08 or greater, or the Narcotics returns a tick symbol back out of the DUI Tests tab in the menu and access Handcuffing, and arrest them for the reason matching their test failure.

Finally, you will need to access the Call Arrest Transport option to call in a van to pick up the arrested NPC.

The achievement usually pops when the NPC is interacting with the transport van.

More of a note than a solution.
Whenever you justifiably pull over a vehicle, you can also justifiably do a drug or alcohol test.
This achievement will stack on DUIs for drugs, amphetamines, or alcohol - so as long as you keep checking everyone you pull over, it should pop relatively quickly.

Another great place to get these is at traffic accidents. There's almost always someone who was DUI.