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Balanced distribution or 'flow' of buses (truck) on the line

Started by EAndrew, September 17, 2022, 08:15:34 AM

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EAndrew

I want to ask others how do you solve this issue. Maybe there is better way than my solution.

In the passenger transport there is overcrowding problem with bus stops in the cities (especially high-density populated areas).
So you have to send more buses on the line.
But this creates the problem that after some time all buses (in this line) catch up one another and drives one right after another.
Than the problem is overcrowding continues because all buses are in one part of the line and not distributed along the line.
Here's a diagram of what i mean:
regula.png

My solution for this problem is to create a distance between buses with Traffic lights.
In the example screen below is traffic light set to stop traffic - red light for 12, and green light for 1. So only one bus is allowed in a period of time.
Downside of this is that the buses are stopped each time when the schedule of line repeats.
That slows down the transportation process.
bus_distance.png

Are there any better ways to solve this?
What do you use?




Maybe you would suggest to use trams or underground trains - there is an easy way to create distance between trams/trains with signals... I know. I used them.
But there is downside of higher cost (tracks maintenance, vehicle cost) and space needed for tracks.
I use high capacity buses Ikarus 280 and costs are lowest than tram/underground/trolleybus. 


makie

wait for minimum loading (for example 50% in the overcrowding station)

or

make timetable in the line with (fixed departure times)
-------------------
signs and signals are for flow control and against deadlocks

wlindley

This is called "bunching" and it is an ongoing, and perhaps unsolvable, problem in real-world transit systems.

Whenever a large group of passengers waits at one stop or station, the first vehicle takes longer than usual to board them.  When fares are collected at entry, this compounds the problem even more.

The second vehicle, running at full speed, closes the gap and now you have bunching.  Repeat until as a passenger you wait and wait and suddenly four or five buses or streetcars all appear together.  At the end of the line, meanwhile, there are now no vehicles to fill the slots in the reverse direction, and the situation gets worse and worse.

Some real-world solutions are having full vehicles not board passengers to try and widen the gap, or running some vehicles with limited stops, or keeping a few 'spare' vehicles at the line ends, or at intermediate points, to fill in.  None of these will eliminate the problem in all cases.

It's an open problem in the field -- and a worthy problem to try and solve in your Simutrans network!

EAndrew

wlindley:
Real world example - this is a timetable for departures of bus n. 13 at a bus stop. (public city transport in a city with population 100k)
During "normal work hours" there are 4 buses each hour.
bus13.png

The bus driver does not sell tickets to each passenger. (tickets are obtain in a ticket machines or SMS or bus card(fare card/pass)) So the bus stops at bus stop for just a moment.

During "normal work hours" there are 4 buses each hour.
This is pretty standard in cities. (Bus/tram/undergound/city trains) And also for inter-city trains.
Im not talking about sparsely populated areas. 

This is nothing new.


Yes Simutrans does simulate the exchange of passengers.
The passenger generation is constant. No extra groups of passenger like in the real world.
Of course vehicles can be delayed by traffic and by exchange of passengers at stops.


makie:
Quotemake timetable in the line with (fixed departure times)
gonna try it! Havent been aware of this new function. (i installed a new version of simutrans recently)

DrSuperGood

In standard the approach is to force waiting for the spacing period at one or more stops in the schedule. There is no penalty for taking longer to complete journeys and the spacing does not need to be perfect, just avoid long periods without service that could cause stop capacity to max out.

In extended the approach is to timetable with the desired frequency at the terminals of a line which can handle multiple vehicles or trains waiting at them. You generally want to avoid excessive waiting at intermediate stops as it lowers average speed which can affect passenger amount. For loops choose one stop to be the waiting stop to space the vehicles out.

In either case it generally trends that 1 of the stops on a line used to wait has most of the bunched-up traffic while the other waiting stops do not. For this reason, I often find it most effective to have just a single stop on a line to space out traffic with sufficient space for vehicles/trains to wait.

Chime

Been playing extended, but can you use road choose signs?

  My experience is somewhat limited from just using horsepower in the mid 1840s but for stops I tend to bulldoze hovels and make a cross off the road with a few stage posts entered via the choose sign road then just keep jamming omnibuses and stagecoaches on the route until I'm happy with the throughput.

  If I notice the coaches jamming up I then come back after I have timing data and set one of the stops that doesn't cross another route to like longest travel time +~10 mins.

  Granted my biggest city is like 150k so this might be impractical past the first industrial revolution.

DrSuperGood

Quote from: Chime on September 22, 2022, 06:00:41 PMBeen playing extended, but can you use road choose signs?
In theory yes.

I have not played recently (~2 years) but there was a bug in the past that periodic timed stops with multiple trains or road vehicles waiting at them at the same time could double book a departure slot. There was also another bug that road choose signs did not always work to dispatch to a free bay but I think that might have also been fixed.

If the stop is a terminal of a route you can usually accept long journey timing unless it is also a transfer point. Under these conditions as long as the load time of the vehicle is less than the period of the route you can leave the vehicles queueing in the road like with standard. This works well for busses which have a fast load time but not so well with high throughput stagecoach routes which have a long load time.