No, too slow might apply only where there are multiple lanes and turnouts, and then only if the driver fails to pull over with five or more cars queued behind them and plenty of space in front of them. So I think on this street even at 2 MPH you cannot get a ticket for going too slow.
The danger is, they cannot ticket too fast drivers. Say the posted limit is 15 mph. If they have not surveyed that street in awhile, they cannot write speeding citations no matter how fast the car is going. So now they survey the street in order to write tickets again. If 85% or more of drivers are going 18 mph at the time they happen to survey the street, they have to raise the limit maybe to 25 mph to remove all doubt. Then they can cite drivers again, but only the ones who are violating that which really means >30mph.
What this potentially will lead to is 85% of the cars going even faster than the 18mph average once the 15mph sign is bumped up to 25 mph, and on the next survey the limit must be increased again.
There’s a direct and much studied correlation between the speed of vehicles at collision and traffic fatalities. What is a small difference in speed in the perception of drivers makes a significant difference between life and death for pedestrians and other road users.
