It's pretty simple - there's a left-turn arrow for westbound cars that stays green for about six seconds. Then the turn arrow goes red, and the bike/ped signal goes green. A new, longer left-turn lane has been installed on Fell to ease some potential traffic congestion from left-turning cars who need to wait for bikes and walkers. And, they have cleared quite a few of the low-hanging branches from the trees next to Fell, so westbound traffic can more easily see the signals and approaching foot and bike traffic.
A simple, elegant way to make the Panhandle safer. In San Francisco. Who'd a thunk it?