"Fixing" the "sims commuting based on shortest distance instead of shortest time" problem isn't necessarily making the engine more "realistic".
Roads in SC4 can get congested, but only up until 30% degradation. Thus, they have "unlimited" capacity. Roads in SC4 will never get overloaded to the point where the sims can't go anywhere. This can happen in SC5 and you need to plan your city well to work around this problem.
Commuting in SC4 is only calculated in terms of work. No leisure time, no transportation of goods or services, (with the exception of freight). In SC5, sims commute for work, for play, for health, for school, etc.
Work commute inSC4 (morning and evening) was also averaged into a single work day, and that's all you'd ever see. There was a morning and evening commute statistic, but never actually happened. You see and experience morning and evening rush hour evolve in your city in real time in SC5.
Buses in SC4 only carried one sim per bus
