Today was... interesting. I ended up having absolute gridlock on literally every major road in my city which put it into a death spiral. I've never seen the Traffic-o-meter at less than 70% or so, and so many dead people and abandoned buildings!
I think it was caused by a loop of queuing motorway traffic from Welwyn Roundal to The Grindstone, as well as a few gridlocked loops within neighbourhoods too. I started out with a population of 75,000. Without any services getting anywhere, crime and deaths caused a mass exodus from my city and my population was dropping at 2,300 cims per minute / day? Lots of abandoned buildings everywhere.
I basically tweaked junction after junction to streamline getting from one main road to another, added a few more sneaky slip roads to main neighbourhoods, deleted inappropriate rat runs slowly the traffic improved. I would find that making small changes to my motorways a "lane gain" (like the north / south image above) so that the mergers didn't have to actually merge onto the motorway would help, and banning right turns at some busy junctions helped out a lot too. At its worst, my population dipped to 49,000, with -$17,000 per minute!
The main problem was waiting for the miles and miles of backlog to clear. After about an hour I'm back to normal. The traffic score is only 50% because there seems to be a bit of a backlog outside of my land boundary...
Ah well, maybe I'll tackle that tomorrow. I'm just glad my city is back to normal!
