Question About High-Mast Lights in Chicago

[Henry]

Normally, there should be a complete set of streetlights to fill out the ring on a high-mast pole, and yet this is not the case on the Dan Ryan and other Chicago expressways, where the half that is facing the highway has lights, but the other half has none. What is up with that?

[Bitmapped]

Why spend money lighting areas that aren't part of the highway, especially when the people living there probably don't want the constant light disturbing them at night?

[SSOWorld]

Why spend money lighting areas that aren't part of the highway, especially when the people living there probably don't want the constant light disturbing them at night?

Makes no sense - the mast lighting is that frickin high up that the areas get lit up anyway.  'sides, it's Chicago.  It's not supposed to be dark there.

[ChiMilNet]

Why spend money lighting areas that aren't part of the highway, especially when the people living there probably don't want the constant light disturbing them at night?

Makes no sense - the mast lighting is that frickin high up that the areas get lit up anyway.  'sides, it's Chicago.  It's not supposed to be dark there.

This is the standard practice in IDOT District 1, which includes basically Chicago and its suburbs. Essentially, they only light up the portion that faces the expressway. Also, you'll notice commonly that there are two high mast towers directly across from each other along the expressway, something also rather unique to IDOT D1. Interestingly, this practice is not quite so relevant downstate, but IDOT D1 has always done their own thing, especially in terms of highway lighting, some of it better and worse than the rest of the state.

[Henry]

Why spend money lighting areas that aren't part of the highway, especially when the people living there probably don't want the constant light disturbing them at night?

Makes no sense - the mast lighting is that frickin high up that the areas get lit up anyway.  'sides, it's Chicago.  It's not supposed to be dark there.

This is the standard practice in IDOT District 1, which includes basically Chicago and its suburbs. Essentially, they only light up the portion that faces the expressway. Also, you'll notice commonly that there are two high mast towers directly across from each other along the expressway, something also rather unique to IDOT D1. Interestingly, this practice is not quite so relevant downstate, but IDOT D1 has always done their own thing, especially in terms of highway lighting, some of it better and worse than the rest of the state.

I can see that. Still, I find it very strange to see only one half with lights, and I do not recall seeing this setup anywhere else. About every other high-mast cluster outside Chicagoland that I have seen so far has full lighting, AFAIK. And as far as having two parallel poles in the same location, I've seen them in many other places in the nation, so it's not restricted to just my hometown.

[Mdcastle]

The way the light shines depends on which direction the reflectors are mounted on the fixture, not which way the fixtures are mounted on the pole.

If you want to light a broad area like an interchange, you use more fixtures on higher poles. If you want to light a smaller area like a linear section of roadway you use fewer fixtures on shorter poles.

[Brandon]

The way the light shines depends on which direction the reflectors are mounted on the fixture, not which way the fixtures are mounted on the pole.

If you want to light a broad area like an interchange, you use more fixtures on higher poles. If you want to light a smaller area like a linear section of roadway you use fewer fixtures on shorter poles.

Problem is, IDOT (especially District 1) likes to use high masts along some linear sections of freeways.  I'm not fond of the things as they tend to scatter light in fog, snow, and misting conditions.  I'm more a fan of ISTHA's approach to just use the lower lighting standards as opposed to the high-mast stuff.

[johndoe780]

The way the light shines depends on which direction the reflectors are mounted on the fixture, not which way the fixtures are mounted on the pole.

If you want to light a broad area like an interchange, you use more fixtures on higher poles. If you want to light a smaller area like a linear section of roadway you use fewer fixtures on shorter poles.

Problem is, IDOT (especially District 1) likes to use high masts along some linear sections of freeways.  I'm not fond of the things as they tend to scatter light in fog, snow, and misting conditions.  I'm more a fan of ISTHA's approach to just use the lower lighting standards as opposed to the high-mast stuff.

I feel that IDOT uses a good combination of both. For example, from downtown going west, 290 has the lower lighting then moves onto the high mast stuff closer you get to Mannheim up until merge of 290 and 355 and uses lower lighting from there up until 53.

But I agree with you, not a big fan of the high mast stuff, I like ITHSA's approach with the I-90 lighting where you have the lower lighting on the median and on each side up until 59 or so and then it's just the median until Rockford.

[westerninterloper]

There are also high mast lights along I-75 between the south I475 and Ohio Turnpike exits near Perrysburg in metro Toledo, though this is only about three miles.

I have always like the high mast lights on the Dan Ryan.

[tdindy88]

The 401 through Toronto, being inspired by the Dan Ryan I believe, has all high masts across the whole city. I want to think some of the other provincial freeways have them too, at least in the city.

[cbeach40]

The 401 through Toronto, being inspired by the Dan Ryan I believe, has all high masts across the whole city. I want to think some of the other provincial freeways have them too, at least in the city.

Inspiration for the 401's core/collector system is often credited to the Dan Ryan, but HML was pretty well just as it emerged in the 1980s.
For other HML use in Ontario, most urban freeways have some HML, or at the very least some interchanges done up with it.