Mission Generation

I second this! The radius is painfully small at times, I very often see calls generate literally right next door to the station!
I have a network of fire, police and ambulance stations in completely real locations (so not unusually spread out) and I see little clumps of ambulance calls around the ambulance stations and police calls around the police stations, etc.
As well as extending the radius the game should generate all types of calls nearby to all buildings on the same dispatch centre - so a police call could generate anywhere within your playing network, not just right next to a police station.

A minimum and maximum radius option would probably be the easiest solution for the devs, and would solve your problem. Or some coding work to make really close calls less common. Third and easiest option, act like it's a walk in reporting to the police or walking up with a medical issue or even pulling up after their vehicle or trailer catches fire. That's how I think of it sometimes.