Pretty neat take on a Crazy Taxi-style game! I like how each of the passengers gave you different effects and restrictions.
My most wanted addition would be to earn time added back to the countdown for every passenger you delivered. It would also help if certain spots reward you more time than others. For example, the destination on the building takes much longer to get to compared to the grounded goals, so that one could maybe give you something like 20 seconds while the grounded ones give you 10 seconds, as an example.
Speaking of the building, since it is the most time consuming one to do, it would be cool if there were shortcuts to reach the top faster. As an example, maybe like a ramp you can use to reach the top faster. It would be faster but also risky since you can miss the landing and cost yourself more time.
I did a few playthroughs and the "Stop at Stop Signs" rule kept giving me paths where I didn't have to cross any stop signs. I would get the passenger and the goal would be right behind me with no stop signs in my path, making it easy to avoid having to use them. Maybe you could implement a check where certain destinations have to be a certain distance away while that rule is active.
Overall, a solid game! Would be cool to see more rules added and to lean into the arcade-y aspect of the game more with the timer aspect. Nice job on this one!