Discription of Events: The person was driving reckless and seemed like a drunk driver. The driver was on a side road speeding. The person was coming up on a stop sign. The driver reduced speed when nearing the stop sign. The driver seemed like they were going to stop for it. The driver decided to not stop and wait for the passing vehicles. The driver took a sudden right turn cutting off the vehicles of a busy main road that had the speed limit of 50 mph. We were the front of the oncoming traffic. The driver pulled out cutting us off with no warning. We had to slam the breaks on to not hit the driver. The person struggled to turn onto the main road. They continue down the main road going about 15 mph to 30 mph. There speed changed alot. The driver was constantly swerving off the road going far past the white line. We kept a distance away from the driver for safety before we turned off onto another road. I did report this to the police for the safety of others.