I was driving home on I-580 around 7:30pm. The distracted driver merged across 2 lanes, and I started to switch lanes when I saw him head towards the center divider. As he continued to switch lanes, I hit the brakes as a natural reaction to avoid crashing into the car, and I didn’t notice the driver on my right side. From what I heard the driver in this incident was OK and caused traffic buildup for a bit. I don’t know what caused them to be distracted.