Spots from lens flare would generally move around, unless the lens has some defect like a chip or a scratch that is causing it.
Spots that are stationary are less likely to be flare, but are probably either a light leak or a reflection from some bright spot in the light path.
From the frame you're showing it could equally be flare or a light leak. It looks like the sun is behind the traffic light, and that would be the ideal situation for getting flare especially with an older, perhaps uncoated lens.
Examine the camera with the lens mounted and the shutter open and look for places that might be shiny.
If the spot is caused by a light leak, it's likely pretty small, and is probably a pinhole in the shutter. If you haven't narrowed things down to a bright spot or flare, try loading the camera and take it out in bright sun, with the lens off. Advance a few frames through the camera by firing the shutter with the lens on and a lens cap on. If you camera has mirror lock up (assuming it's a 35 mm SLR) use the mirror lock up. If you have any density on those frames, then a light leak is the cause.