Negligence, in legal terms, is a very specific set of material facts. In general, you establish it by proving a defendant had a duty to do something and subsequently failed in that duty, causing an injury to you, the plaintiff. Drivers have specific responsibilities out on the road, and it is relatively easy for lapses to result in lifelong consequences for those behaving exactly as they should.
Janitors are vital to our workforce and society at large. Custodians and housekeepers keep our offices, schools, museums and hospitals clean. Without janitorial workers, our society would not be nearly as clean or healthy. Sadly, cleaning employees are often not valued.