Different timed traffic light programs, configurable per daytime interval

[VictorPhilipp]

http://steamcommunity.com/workshop/filedetails/discussion/583429740/357286033299200961/

VictorPhilipp/Cities-Skylines-Traffic-Manager-President-Edition#26

[originalfoo]

This would be essential if we were to also implement "Tidal Lanes" #122

[VictorPhilipp]

Migrated comment:
"At specific intervals, priority signs may take over controlling the junction. The traffic light then flashes yellow. (@GordonDry)"

[VictorPhilipp]

Migrated comment:
"Not sure if this should go here, but here goes:
Provide the ability to mark one state of a timed light plan as the "default" or "rest" state. I'll give an example to demonstrate the use of this feature.

There is an intersection of an arterial road and a collector road. There needs to be a traffic light (instead of priority signs) because there is a heavy volume on the arterial road. The volume coming from the collector road is very light. We have a timing plan such that the maximum amount of time cars would have to queue on the collector road is 45 seconds (aka the max timer of arterial road). The arterial road is in a green state, the max timer has started counting down from 45, but there are no cars in the queue on the collector road. The states will cycle at the end of 45 seconds, even though there are no calls for service on any conflicting movement (wait = 0). The arterial road will cycle to red until all the other states are cycled through. If we could set the state that serves the arterial road as the "default" or "rest" state, then if the wait value is equal to 0, it would not cycle to the next state.

Ideas:

1. If the active state is "default/rest", and wait value = 0, then do not start max timer. When wait value > 0 (a car has queued for service on a conflicting movement), begin the max timer. The max timer runs out due to heavy volume, and the state terminates as normal, moving to the next state in the timing plan.

2. If the current state is NOT the "default/rest" state, and flow = 0 and wait = 0, immediately terminate the current state and jump to the "default/rest" state (regardless of current position in timing plan).

Assumptions:

1. Players would (optionally) indicate which state is the "default/rest" state in their timing plan (state with heaviest anticipated volume/flow).
2. If player does not designate the "default/rest" state, the timing plan will operate as it currently does."

[brazenest-zz]

Do we have an estimate of the work required for this feature? Reads like "rest on green" would be a minor mod of the timer.

[originalfoo]

Part Time Signals

In UK, usually on roundabouts near motorways (highways), traffic lights often only operate during rush hour or certain times of day. In evenings or when there is low traffic they switch off to allow traffic to move more freely (follow normal priority rules, with traffic usually yielding).

https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/9209/traffic-signals-low-demand-periods.pdf

There are also trials of using them on slip roads for traffic joining a motorway during rush hour: https://www.youtube.com/watch?v=xv6DOvNfzVQ

The part time signals are usually visually different to normal signals; part time traffic lights generally have a big yellow border around them as shown in video above (unlike the small white border as shown in image at the end of this comment).

Part time signals can't be used when there is a pedestrian crossing controlled by same signals (although vehicle-only signals on same road can still be part time) - visually impaired people wouldn't know if they are on or off: http://www.roadsafetyknowledgecentre.org.uk/help-forum/835.html

Where part time signals exist (in UK at least) they are accompanied by this traffic sign (in which case traffic would use normal priority rules):

However, in some cases traffic must stop rather than yield, in which case this sign is used instead:

[originalfoo]

In some countries traffic lights just have a yellow flashing light when 'not in use'.

Some info in wikipedia: https://en.wikipedia.org/wiki/Traffic_light_control_and_coordination#Other_types_of_control

[originalfoo]

Note that if we could detect power failure (as the game does for buildings), that could also affect traffic lights. Will create new issue for that.

[originalfoo]

Part time signals could be dependent on traffic volume; if there is low traffic the lights could be disabled.