Lane merging & splitting (on highways)
When exitting/entering a highway, in real-life vehicles switch to/come from a designated lane. These so called deceleration/acceleration lanes are needed in order to maintain a steady traffic flow on the highway and to ensure safety. Again, there are rules how highway lanes are merged or splitted.
Traffic Manager: PE implements these rules for all highway roads if you enable highway specific lane merging/splitting rules.
Note: To work optimally, there should always exist exactly one outgoing lane for each incoming lane.
When you enable highway specific lane merging/splitting rules the lane arrow changer for highway lanes is disabled because the arrows are automatically set by the highway lane selection rule set.
[Blockierte Grafik: https://www.viathinksoft.de/tmpe/pics/lane-splitting-1.png]
In an optimal setting each incoming lane leads to one outgoing lane.
If there are less outgoing than incoming lanes, vehicles merge into the reduced set of lanes.
[Blockierte Grafik: https://www.viathinksoft.de/tmpe/pics/lane-merging-a.png]
[Blockierte Grafik: https://www.viathinksoft.de/tmpe/pics/lane-merging-b.png]
Vehicles merge when lanes end.
Be aware: Lane splitting/selection strategies on highways differ from those on city roads. Keep that in mind when laying out roundabouts, one-way streets and especially when creating junctions with city roads.
I suggest you to subscribe to the Network Extensions Project mod to get a variety of addditional roads including both city roads andhighways.
[Blockierte Grafik: https://www.viathinksoft.de/tmpe/pics/diff-lane-split-1.png]
City road lane selection: Since the 3- and 4-way one-way on the upper half is a city road, the city road lane selection procedure is applied (see section "Lane selection at junctions and transitions").
[Blockierte Grafik: https://www.viathinksoft.de/tmpe/pics/diff-lane-split-2.png]
Highway lane selection: When both one-ways are replaced with their highway pendants, the highway lane selection procedure is applied.
If you only want to use city road lane selection in your entire map you can disable highway specific lane merging and splitting rules by deselecting the checkbox.