In my city, traffic is not an issue. I watch the garbage and recycling trucks travel the city every day.
For me, the problem is starting at the trade depots. For some reason they are NOT exporting goods. Most of my city income is in tourism, but at some point I had the "brilliant" idea (with the game's prodding) to restart my processor and electronics factory. Instead of supplying the raw goods from mining and a refinery, I've been using reclaimed plastic and ores. It worked for a period of time.
But then the depots stopped exporting. ALL of them. So TVs, computers and processors stack up in storage lots ... then the factories shut down because they have nowhere to send their finished products (since the depots are full), so THEN the recycling facilities get backed up because there is nowhere to send plastic, metal and alloy. THAT leads to complaints from city hall about garbage in my city. The truck are traveling but they can't drop anything off.
It's just a huge chain reaction.