1/700 At 3: 40 a.m. one day, Mr. Sun drove a large bus with 54 passengers(capacity 55 people). At the spot of 229 kilometers mark by 300 meters on Suiyue Expressway, the bus had a rear-end collision with a heavy semi-trailer driven by Mr. Li when passengers were getting off from the bus. As a result of the accident, 26 people were killed and 29 injured. According to the investigation afterwards, Mr. Li had been driving the bus since he left the place of departure at 6 p.m. the day before without any rest. What are the main illegal acts of the two drivers?