Rating a trip in a way that is actually useful
Five stars for everything makes ratings meaningless. So does one star for traffic.
Ratings only do their job if they carry information. Two habits destroy that: rating everything five stars regardless, and rating down for things the driver did not control.
What is in the driver's control
Whether they took a sensible route. Whether the vehicle was clean and roadworthy. Whether they drove safely. Whether they were courteous. Whether they arrived where you asked and confirmed the PIN properly.
These are fair grounds for a rating in either direction.
What is not
Traffic. Rain. The fare, which was computed before the driver was assigned. A route that looked longer but avoided a jam. The weather at the airport.
Rating a driver down for the Ring Road at six in the evening is understandable and unfair, and it degrades the signal for everyone.
Say what happened
A rating alone is a number. Where something specific happened, good or bad, the comment is what makes it actionable. "Waited at the wrong gate despite the note" is useful. "Bad trip" is not.
Safety issues are not ratings
If something felt unsafe, that belongs in a report against the trip rather than in a star rating. Reports reach the safety desk with the trip attached, and patterns across reports are what allow fair action. A one-star rating with no explanation does not carry that.
It runs both ways
Drivers rate riders too, and can report them. Being ready at the pickup, being where you said, treating the vehicle decently and paying without argument are the things that make you a passenger drivers are glad to accept.
Why bother
Because the alternative is a system where every driver has 4.9 and the rating tells you nothing. Ratings that mean something are a small collective effort, and they are the mechanism by which good work becomes visible.