There’s been a lot of discussion about the Cities Skylines simulation since the game launched with players concerned about workers not getting to work, traffic, and so on. A post from Colossal Order’s Kaorliina Korppoo, who is Lead Designer on the game, sheds some light on the mechanics which should help players understand the game a little better and help them make decisions.
All workers do not need to get to work. This would simply need too much processing power if all 1 million citizens left to work at the same time. The worker numbers shown in factory information windows are the employees assigned for that building, the ones who can visit it as a work location. Not all of the workers will visit the building at the same time, some might not ever visit it, but they are the ones marked to work in the building. Employees don’t need to get to work, but there need to be enough people in the city to assign to each workplace.
If citizens get stuck in traffic they will return to their starting point and abandon the traveling. This mechanic prevents city-wide gridlocks from happening, because when the traffic got that bad, it was very hard for players to see where the actual problem was because the traffic info view showed all roads as congested. Now the traffic jam will stay, but not expand uncontrollably, so it can be found and dealt with. Traffic jams do affect the city, because citizens can’t travel to shopping locations, tourists can’t travel to shopping locations, goods don’t ship to local businesses and raw materials don’t reach the industry.
Industry needs connections to receive raw materials and ship goods to outside locations or businesses in the city. For the most tax revenue, you should produce raw materials locally, have industry make them into goods and have local shops sell them. The shared save (Worker bug) has a city that does not even cover the upkeep of the roads with the industry taxes because they do not ship to local commercial areas. All buildings spawn with a small buffer of the items they need (goods for commercial, raw materials for industry) and will only require a shipment once the buffer gets low. In the save’s very small city the buffer lasts quite a long time, but if you let the save roll on top speed for about 15 minutes, the buffer empties and commercial starts to need more goods. In a larger city, the buffer is gone fast and thus buildings react to poor connections faster.
So basically goods and raw materials work as agents, but citizens are a combination of agent and statistical model. A good road network makes the city produce more tax revenue, and having public transportation to take citizens to work will benefit the player by generating ticket income. Tourists only spend money in the city if they can reach commercial areas.
The city is quite slow to react to changes, but this was a choice made for stability so you can’t accidentally destroy your city by a few poor choices. There’s always time to react and fix things.