empty lane change permissions cannot be declared

[m-kro]

The lane change permissions (changeLeft and changeRight) are not saved to file when editing in netedit, saving and reloading it.

Process:

• create multilane edge in netedit
• set custom changeLeft and changeRight values
• save the network & reload

Result: The changeLeft and changeRight attributes still default to all, although all vehicle classes had been forbidden.

[namdre]

changeLeft and changeRight are like an "allowed" attribute. The attribute cannot be empty. If you want to declare that nobody can change, we would need to introduce a new "magic" value like changeLeft="none". The recommended solution is to declare changeLeft=emergency" and thereby exclude all "normal" vehicles (also, emergency vehicles would typically ignore such restrictions).