Cities: Skyline services going to the wrong districts

I have a city divided into several districts.
The districts are interconnected with subways and highways.
Each districts supplies its own power, and has its own services.

However, some of the services have started going to the wrong, distant, districts.
Most notably, my fire-department seems obsessed with letting firetrucks from a district that's geographically close but a long drive away deal with their fires.

I added a screenshot with an example firehouse, and a frequently burned down building.

I don't understand the behavior, upon placing the firehouse it does seem to reach the house, however it has two firehouses much closer.
This also has the added downside that these houses seem to be high in Fire Hazard despite having two nearby firehouses.
And as an additional downside, firetrucks and garbage trucks crossing districts is causing unneeded load on my district connections.

So, to recap, my questions are:

1. What causes this behavior?
2. How can I prevent it from happening?

Solution 1:

Districts don't actually do anything to restrict or direct services. Services will be user for whatever is in their local area, regardless of district boundaries (exceptions for power and water, as you distribute them manually).

Districts are useful for:

• industrial specialisation (agriculture, forestry, etc)
• policy specialisation (education boosts, tax cuts, etc)
• controlling lorries (technically a policy specialisation, by way of the heavy traffic ban, but this is important enough to warrant its own entry!)
• adding personal flavour to your city.

On that basis, the game doesn't care what districts your fire stations and fires are located in, which is why this can happen.

As to why it sends fire engines from a distant station instead of a local one (and thus, how you can prevent it), well... I'm not sure, but here's a few thoughts that may help:

• Are all the engines from the closer stations in use?
• Is that road in the middle, where the fire is, one-way in the up direction? If so this makes it "further away" from the stations on the right that it seems, and would be why it's a greater fire hazard than you might expect. It might also be confusing the distance calculation (and thus the selection of station) - consider moving one of the stations on the right downwards.

Solution 2:

This issue also frustrated me, so I ended up writing a simple mod for fixing that: http://steamcommunity.com/sharedfiles/filedetails/?id=649522495

Be sure to read the full description, it has a few limitations.