I hope this isn't just focused on just the CBD alone, some parts of the network are just hopeless due to the sheer amount of cars that absolutely have to choose the centre lane with the tram tracks for no reason whatsoever. I have been stuck on the 75 several times where every car has been bumper to bumper in front of the tram (Camberwell Rd is the absolute worst), yet the left lane has been completely empty! I'm sure it happens everywhere thogh, I know the 16 on Glenferrie Rd is just as bad, likewise the 58 along the entirety of Toorak Rd (and the eastern part of the 75 on the same road - the area near the Alamein line rail bridge is particularly annoying as cars park next to the bridge).
That said, I'm all for installing bumper-damaging concrete kerbs along the entirety of St Kilda Rd and Flinders St. Given that everyone drives SUVs these days the height should probably be similar to the platform stops in order to get the message across. Taxis and vans chucking a U-ey in front of a tram instead of the designated U-turn area 50m away can then be laughed at when their bumper gets torn off or they end up marooned on a 4 inch wide piece of concrete.