What are prerequisites for arcing?
Each insulator (air is one) has an specific minimum voltage/distance ratio for an arc to appear.
Those probably wouldn’t arc even if their surface was electrified. But as a sibling already noted, their surface is insulated. They would be extremely sensitive to any kind of dirty, though.
Elon Musk apparently doesn’t. Otherwise he would learn some bit of it.
Anyway, let them fight :)
there’s an island that makes crossing easier
As people already pointed, a fenced island. It looks better in a photo, but that’s not where people will be.
But yes, the speed of the cars is probably lower.
Hum… Have you seen any actual improvement?
Because it doesn’t look more dense, it doesn’t look more walkable, there’s a bicycle parking spot but there doesn’t seem to be any reason to bike there…
Power lines need way less maintenance if you bury them.
Orders of magnitude less maintenance.
If you want to look:
https://en.wikipedia.org/wiki/Breakdown_voltage
https://en.wikipedia.org/wiki/Paschen's_law
Technically there are no arcs in vacuum. Things work differently there, the discharge voltage depends on the electrode material and temperature.