Police stops female drunk driver

Police stops a drunk driver at night in the rain. In the middle of the street. She is obviously soaked, she is wearing a thin dress. He makes her walk back and forth for the longest time. She is nearly falling and obviously drunk. I did not understand why he did not just arrest her. This cop made it a long drawn out process. I can not pass because his police car is in the middle of the road and her car is also parked in the middle of the road. My camera battery finally died and this went on long after my camera died. Police officer finally came up to me and told me I had to turn around and find another way home. Something fishy going on here...