If you open the front door when you get on the bus and find something in the passenger seat, for example, the female driver will put the bag in the passenger seat, and the male driver may put some other items, such as mineral water, lighters, mobile phone maps and so on. As long as there is something in the passenger seat, I suggest you sit in the back seat.
If the driver is a female driver, then as a male, you'd better sit in the back row. If you sit in the co-pilot, it will not only cause some pressure to the female driver, but also cause other unnecessary troubles.