All those SimCity peculiarities relating to Sims and vehicles are in fact a fault with the game, lead designer Stone Librande has admitted in a blog post.
The good news is that an upcoming update will fix all this.
"Now that we're getting close to resolving our server issues, we're putting a lot of attention on improving the simulation based on the community's feedback.
"SimCity is built on GlassBox, which is an agent-based simulation engine. At the surface level, GlassBox is designed around the premise that "Agents" are created to carry data to various "Sinks" around the city. In SimCity, you can think of the "Agents" as Sims and vehicles. The "Sinks" are the buildings that receive money, happiness and other resources from these Agents. During development we tested many cities in a variety of scenarios, but there are almost limitless permutations. Now that the game is in your hands we are seeing the emergence of many cities that test our systems in unique ways. It's great to watch this happen because at its core SimCity is a game about experimentation and exploration. (Of course, it's not so great when these experiments reveal bugs.)
"We are constantly tuning the game and through the telemetry of our players we are shaping and evolving the experience to accommodate many different play styles. When bugs are discovered we will address them as quickly as possible, with updates such as the ones we've been rolling out over the past week. Our main focus right now is updating the pathing system that the Agents use to get to their Sinks. Running a successful city means keeping the traffic flowing and we are actively working to make this system better.
"We understand that when cars always take the shortest route between point A and point B there will be unavoidable (and illogical) traffic jams, so we are retuning these values to make the traffic flow more realistically. Guillaume Pierre (our lead scripter) talked a bit about the improvements that we are making to the traffic system in the game here. To dig a little deeper our roads will have a weighting system based on 25%, 50% and 75% capacity. As a road hits those marks it will become less and less appealing for other cars, increasing the likelihood of them taking an alternate path if one exists.
"We are working on additional fixes with the pathing of our Agents and these changes will streamline the way that the simulation unfolds in your city. For instance, emergency vehicles will not get blocked in their garages and will move into empty lanes to get around traffic jams. We're also working on preventing service vehicles from clumping up (for instance, only one fire truck will respond to a fire instead of two) and improving the way that Public Transportation operates in the city. We are currently testing a patch internally and hope to have it out to you soon."
Librande concluded: "I want to end on some good news. We are slowly re-enabling some of the non-essential features that we had turned off during the week of launch. Regional Achievements are live on a select number of servers and we've re-enabled Leaderboards on the Test server. We need your help testing the Leaderboards so I encourage you to go to the Test server so that we can expedite the timeframe in which this feature is brought back to the rest of our servers."