Yeah that's a massive problem in London as a driver. While I certainly respect cyclists (as a former cyclist) it really annoys the hell out of my when someone comes flying at me on the opposite side of the road with a frigging strobe light going on. I can see you fine if it doesn't flash.
The slow flashing ones are quite dangerous as the only light (and not generally lawful in the UK*). I remember pulling out of a junction having looked right-left-right and nearly hit a cyclist coming from the right whose light was off both times I looked in his direction. It must have been around 1-2 Hz. When I cycle I never use the flashing modes for this reason.
Coming back to streetlighting. Around here (Southampton UK) it was mostly LPS, with occasional HPS on major roads until maybe 5 years ago. Now residential areas are mostly fluorescent (!?) and dim or turn off from 1 am, most of the major roads are LED with some HPS left at big junctions.
Modern regulations requiring full-cutoff luminaires that do not emit any light above 90 degrees also create a problem of needing more of them to create even illumination and even then you end up with bright pools under the source with dark spaces between.
The problem is retrofitting full-cut-off without changing anything else like pole heights or spacings. It's cheaper but you get this effect.
I can remember sections of the M25 having LPS on catenaries up the central reservation, like this
http://imagizer.imageshack.com/a/img922/9831/kq2AUC.jpg I seem to remember the light was fairly even, but it's all gone now in favour of conventional poles. Perhaps maintenance is just easier/cheaper. Not all UK motorways have lighting, mostly the larger, busier ones and around junctions.
*You are allowed to use a light that flashes if it is CE marked and has no other modes. From memory though this is to meet the requirement to have lights, once you have a light that meets this you may be able to add additional lights of any type, not sure.