I had huge traffic jams in Berlin during the first scenario. It took a LOT of rebuilding my lines and stops to reduce the traffic jams to acceptable levels - but it taught me a lot about what to do, and what NOT to do! Later Berlin scenarios were not as bad, because I made sure to avoid repeating the same line mistakes that caused jams the first time.
I applied the patch before I ever started playing, so it did not affect my feelings about traffic levels in Berlin changing.
Berlin was also the first city where the "Vagabond" tram had a repeatable sticking point (bug) that caused huge traffic problems near the NorthEast railway station during my first scenario there. I avoided using these trams ever since.
Also, the Southern railway station (apologies I forget it's name) was the main cause of my early jams. I had a lot of connecting lines near it, and the roads around it were just too small. It is demolished and changed into a business park in later scenarios, which might account for the drop in traffic. Railway stations seem to be the biggest concentrated source of people and traffic in CiM.
If you are not playing the campaign, then you can set traffic level independently under "Custom" difficulty. You'll want to be choosing 100% traffic all the time.
If you are playing the campaign, then your choices are limited to Easy (60% traffic), Medium (80% traffic) and Hard (100% traffic), but this also controls starting money and refunds from demolitions, so it's not that easy to switch. You can choose Custom difficulty when replaying a scenario map after it has been unlocked by completing it during the campaign, so you can try it again with more traffic later if it's too difficult to play the campaign on Hard.
PS Congratulations on being probably the first player ever to ask for MORE traffic in CiM!
