It looks like the engineers were testing out the new lights on the bay bridge. I took the opportunity to quickly snap some photos.
I shot these out of the window of my apartment, semi-handheld. I rested the camera on the ledge of the window and then snapped about 10 photos. I stacked the images and then applied a median blend on all of them to reduce the noise. If I had a tripod, I would have done a long exposure.