Speed limits - underground view

[originalfoo]

While testing PR #1215 I noticed some potential issues with underground view:

tagging #1221

Icon placement

Is it possible to get the icons better positioned to the tunnel?

Lane/segment highlight

Green is low-contrast in the greyscale underground view. Maybe a red or dark green would be better?

(Note: Move It mod also has same contrast issue with its blue highlight color)

Overground icons?

Are overground icons supposed to be visible? I noticed that the underground icons have a small v marker on them, which I assume was to differentiate them from overground?

Likewise, in overground view, the underground icons don't appear:

Not sure if that is intentional or not. Personally I prefer seeing both, as it makes any manually customised 'speed gradients' going in/out of tunnels more visible. I usually slow traffic a little as it enters/exits tunel. Maybe a mod option to determine behaviour (show both, vs. view specific)?

Edit: Instead of mod option, have a small v button on the speed window to toggle whether underground and overground are shown at same time?

[originalfoo]

Would the small v overlay be better placed top-center?

Also, something like that overlay could be used to indicate when average speeds are being shown - maybe a ~ bottom-center?