The problem I've seen around here is replacing "normal" streetlights with those stupid highmast things. Lets redesign a freeway interchange and remove the roughly 3-4 dozen 200w HPS streetlights and replace them with 8 highmast poles with 6-1000w HPS (or LED equivalent) fixtures on each pole .

Tim, I understand your point, but most likely this has to do with the age of the old system. Most freeway interchange lighting systems were installed back in the 60's using MV first, then lumen equivalent HPS.

I understand that the system was old and due to be replaced. But I don't understand why the new system need to produce so much light . You can literally see the interchange from close to 10 miles away at night ! The previous light levels were more than adequate .

Apparently at least according to the MTO here, the fewer number of lamps and luminaires from using highmast to light an interchange makes it easier to maintain compared to the old conventional poles with cobraheads. Almost all the large freeway to freeway interchanges here were converted from their original 1960s era cobrahead poles (originally MV, later lumen matched HPS) to HPS highmast starting in the late 1990s.

Apparently at least according to the MTO here, the fewer number of lamps and luminaires from using highmast to light an interchange makes it easier to maintain compared to the old conventional poles with cobraheads. Almost all the large freeway to freeway interchanges here were converted from their original 1960s era cobrahead poles (originally MV, later lumen matched HPS) to HPS highmast starting in the late 1990s.

I looked on street view on Winnipeg and that’s what they have done, IIRC I think they used to have LPS for their highways, my memory could just be playing tricks on me though.

Here’s a survey done in 1979 about the benifits and drawbacks of low pressure sodium street lighting by cities in California. Unfortunately, the lack of color rendering led to most cities not using them.

Interesting reading, it’s clear though, people in the US still prefer their mercury lighting 

Here’s a survey done in 1979 about the benifits and drawbacks of low pressure sodium street lighting by cities in California. Unfortunately, the lack of color rendering led to most cities not using them.

This is one thing I've never understood. You don't need colour rendering from street lighting when driving, you have perfectly good headlights for that. You need contrast and to be able to cut through fog and mist, which LPS excels at 

A handful of cities actually liked the idea of SOX and seriously considered using SOX because the benefits outweighed the drawbacks (kinda like mentioned earlier in the thread), the only issue was residents from those cities complained.

They believed SOX made their cities look unattractive, particularly in business districts, and had a negative impact on fighting crime. Take Long Beach for example. They chose SOX for its efficiency and in response to the energy crisis in 1978, but that was short lived.

That's sad. To me, LPS (I use the term rather than SOX, as my all time favorite has to be SLI/H) is the most amazing lighting ever. I have never liked white light for street lighting, for me it's always been the soft amber glow of LPS and latterly the golden tones of HPS. There's just something about it that makes me smile, and it saddens me more than I can say that it's gone forever, or will be very soon 

I've always preferred the higher contrast of HPS, especially during inclement weather while driving over LED or metal halide. That being said, I think for downtown high streets, metal halide or even deluxe mercury vapour looks a lot better than sodium lighting. 

It is sad. Now L*Ds have taken over the entire lighting industry, pretty much everything has gone LED in my area. I remember the SOX lighting here in California back in 2011. The Norelco SRP was very unique and was one of my most favorite fixtures to look at. Their deep yellow light was hard to miss driving down the freeway. Now it’s all boring LED spatulas.

I've always preferred the higher contrast of HPS, especially during inclement weather while driving over LED or metal halide. That being said, I think for downtown high streets, metal halide or even deluxe mercury vapour looks a lot better than sodium lighting.

Well LPS will always win out in a contrast competition, but I do like HPS as well. We used to have a mixture of MH and HPS here, and if I had to choose between the two, then it has to be HPS. I just don't like white light at night. Also, with her poor eyesight and night blindness, Sammi can't see properly under it 

I found out something interesting about SOX light the other day. I picked up a calendar with small printing on it and for the first time in years I could read what it said without have to change from my distance glasses to my reading ones, so for me SOX or LPS is the best type of lighting out there. I can see perfectly to drive, unlike with the current crop of lighting that mimics the night time sensitivity of the human eye. I have night blindness, so that's the worst light possible for me and I need to hand over to Ria for the driving duties. 

Well LPS will always win out in a contrast competition, but I do like HPS as well. We used to have a mixture of MH and HPS here, and if I had to choose between the two, then it has to be HPS. I just don't like white light at night. Also, with her poor eyesight and night blindness, Sammi can't see properly under it

My grandma’s night blindness is so bad, not even HPS lighting helps her see at night. 
I’ve always liked the look of clear mercury vapor bulbs. It’s also good to note that I’ve always liked light sources that have a color temperature of 5000K or higher. My mom, on the other hand, prefers HPS and color temperatures 4000K and under. I don’t mind warm white lights, but if given a choice, I’ll go for 5000K daylight or higher. Sorry for the long post. I like to include a lot of info. 

There's the difference between us, I can't stand high colour temperatures, for me it has to be 3000K or lower. The best white light source I've come across is the 23/25W PAR38 self-ballasted metal halide lamps, at 3000K they're perfect for me when I have to have white light. Which isn't often, most of the time our place is lit with 35W SOX