The variables in the quality of driving are far from being a few, and include: - driving aggressively/dangerously/poorly - the above includes not being focused

The variables in the quality of driving are far from being a few, and include: - driving aggressively/dangerously/poorly - the above includes not being focused on driving (eg. talking on the phone) - reacting angrily to other drivers - driving illegally - allowing a ride without safety measures (eg. child seat), which is also a case of driving illegally - not replying to requests (messages) at all before actually starting the ride (which is important in case of particular needs), leaving the passenger without answer until the vehicle arrives All of those are important, and they definitely need to be all provided - as a matter of fact, at least some are provided in case of ratings below 5. Uber's star rating has a sensible design - anything below 5 requires the user to explain why. However, I believe that this skews passenger ratings toward 5 stars, even if just for the effort required, or even worse, because of the perception of hostility (AFAIK, ratings are given immediately, and the driver can get an idea of the rating of the passenger).