Continuity mistake: After Victor leaves the warehouse, Axel fights off the remaining thugs. He throws a guy into some boxes, and 5 seconds later, the exact same shot is repeated.
Other mistake: If Rand was responsible for investigating homicides in Detroit, it is doubtful that he could have stayed behind a desk for 12 years.
Answer: There might be a deleted scene showing an extended chase scene, but as it is, it seems out of place. From what I can tell, the road was slick, like something oily was spilt on the road during the chase. I don't think it's from the fruit and vegetable truck either. The bus looks like it's breaking suddenly (perhaps to avoid an unseen wreck) and skidded out and the driver over compensated, spinning the bus out. In fairness, a licensed bus driver would probably be able to control the bus in that situation, so it was exaggerated for the film. It probably should have been cut, but I'm guessing someone liked it and kept it in for more action.
Bishop73