Running on 7.8.155
There have been a cluster of issues affecting my city and I have been reworking it to improve traffic efficiency. However, it looks like there are some bugs compounding the problems.
Note that I almost exclusively use 1-way roads and segregate traffic types as much as possible to avoid some types of congestion. It does mean that the route pathfinder sometimes finds a tortuous path through multiple districts that I wasn’t expecting; that is not a bug per se, but might be relevant for the first item.
The Player.log contains quite a few messages about:
Car hasn’t been updated in 200 simulation frames. Destroying
For quite some time I have needed considerably more production capacity for residential goods than the consumption figures indicated. While the city was being built-up, I attributed it to the demand surge caused by new and upgrading habitats and then later the destroyed cars messages. During my redesign work, the residences reached a steady-state and so that should have tapered off. I could shave the production capacity somewhat, but for high volume goods like school, culture and the park, if I went below 120-130% of expected consumption, residences would start to complain of shortages. Low volume goods like home robots are less demanding.
The supply and demand filling algorithm appears to have an issue. When I moved several level 6 residences from the old road network to a new one which has a large independent Oxygen supply, it flooded the new area with Oxygen trucks. One residence was topped up and then had 12 more Oxygen trucks in quick succession waste their contents by topping up nearly full tanks in the residence. After that, the flood abated, but these buildings continued to receive small waves of deliveries in excess of what they could hold.
Similarly, I found a motor factory in a district that at the moment has more production than needed. When the factory periodically made a delivery, a wave of copper and steel deliveries in excess of the available input storage capacity were dispatched.
Given district level worker allocation one could tune things to avoid traffic jams from floods of excess deliveries, but smarter dispatching would reduce a heavy production tax.
Savefiles and the Player.log are available if needed.