Traffic bug – Train Fever

Traffic bug

natvander — Fri, 12 Sep 2014 09:32:06 +0000

In my late game (post 1970) I have a high speed line between two cities. My passenger numbers on both train and bus are gradually dwindling. Train carries on average about 30 passengers each trip. The road traffic on the road connecting the two cities is horrendous. Massive traffic jams.

I ended up cancelling the train and the traffic between the cities stopped. The only traffic to be seen were my freight trucks. When I recommended the service, the traffic jam returned.

Reply To: Traffic bug

mackintosh — Fri, 12 Sep 2014 09:39:14 +0000

Interesting, I haven’t noticed this before, but then I hadn’t tried to cancel the trains. From your description I infer that the AI does not compute nor contemplate inter-city travel unless there is a line connecting them. It would seem that only then does it attempt to move people from one city to another. The reason for the traffic jam is simple enough – the AI finds making the trip by car faster than by your train. Improve frequencies and feed more people to your station via intra-city transport. Failing that, bulldoze a bit of the road between the two cities – though that is technically an exploit.

Reply To: Traffic bug

natvander — Fri, 12 Sep 2014 10:40:17 +0000

The odd thing is I can’t see how the trip by car would be quicker than by train. The train frequency was around 3-4 minutes – any shorter and each train would be lucky to have 15 passengers. Train speed was up to 200kmh. I watched one of my trucks caught in the jam travelling to an industry half way between the towns and the train must have passed it at least 10 times. Each bus or tram route in either city has 3 vehicles per line and max frequency is 3 mins. Each city has 3 or 4 lines and each land use is connected.

I think you’re right in that the AI doesn’t detect an inter city connection unless you make one. Once the connection is severed, the AI ceases to see the connection. I found it amusing that I provided a fast connection but the agents would rather sit in traffic. When I took the service away, they no longer wanted to travel.

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mackintosh — Fri, 12 Sep 2014 10:56:01 +0000

Keep in mind that the whole trip time is walking time from point of origin + waiting time + intermodal travel time + time to walk to destination; a car trip is direct A to B. It is possible that all the trip parts are too long for the majority of your population.

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Vaulter — Fri, 12 Sep 2014 11:04:19 +0000

a car trip is direct A to B.

through a giant jam its almost endless

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mackintosh — Fri, 12 Sep 2014 12:09:48 +0000

Can’t answer that without knowing how the agents are simulated in this particular game. I seem to remember that in Simcity the agent wouldn’t take traffic flow into account and push through the most congested areas. Perhaps it’s the same here in that the agent calculates trip time based on path alone.

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CalDMint — Fri, 12 Sep 2014 12:17:27 +0000

When this happened to me with my TGV service, I had to increase frequency (cut down to the 200kph trains you mention) and also the bus feeders seem to work best at 60seconds or less frequency in my experience. Also, where I had to look was at traffic inside the city. This same traffic jam was killing my bus/tram routes. So add bus lanes, create diversion roads for cars, etc. you need to make sure your feeder system flows and flows quickly.

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Azrael — Fri, 12 Sep 2014 12:56:44 +0000

I also experienced huge traffic jams near my biggest city in my first game and I had a very good public transport and rail system (frequency of rail lines 3-4 minutes, about 45 sec frequency for the 4 Public transport lines).
And despite my good service, the majority still went by car. I achieved “The smell of success” in the 1880’s but I never reached this number again in the age of cars, though my trains weren’t slow or empty.

I think, they should patch the travel time calculation for the population, so they take traffic jams in account, otherwise this feels so wrong, when you do everything to shorten the travel time and they still fight their way through a huge traffic jam…

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RickD — Fri, 12 Sep 2014 15:23:51 +0000

the game doesn’t take into account traffic jams. It calculates travel time between home and work / leisure using the 2 routes and takes whichever is faster, however it only bases this travel time on the speed of each vehicle potentially involved…

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Yeol — Fri, 19 Sep 2014 07:02:15 +0000

I experienced the same weird behaviour with traffic jams. When I install a transport service in the city, traffic grows and end up in a huge traffic jam; all streets clogged up to a stand-still. When I sell all vehicles and stop transport services, all traffic vanishes after a few years, and streets are clear. Very strange!

So, there are a few proposals I like to formulate to tackle the problem:

please, magician-developers, review the traffic algorithm, there is some strange coupling between the public transport opportunities, and the fact the people decide to take the car.
take in account the current speed (and not only maximum speed) in the street(segments) to decide if a route is faster by car or not.
have made some tools available to us (gamers) to counter traffic jams and convince people to take the train/tram. Normally it should be to install public transport (bugged), but other measures could be like adding parking facilities to railway stations (eg an upgrade option to the station) or building underground parking lots near tram stations.
I never got bus lanes working, but probably it’s my error.
…

Traffic jams are at the moment game breaking, because they tent to snowball out of control. Especially, because one expects that by added public transport the number of cars on the road should get lower, but on the contrary, it increases! The only answer to the jam, is stopping all transport services in that city and selling all vehicles. And that is probably not the way the game should function, I think.