High-mast lighting on sides of the freeway (as opposed to middle)

[andrepoiy]

I have come across some places where they put high-mast lighting on the side, rather than in the middle of the freeway.

I find this to be rather wasteful, since that would be wasting the light on the "outer ring" of the lights, where it's lighting up the side of the freeway rather than the freeway itself, I don't know if you know what I mean.

In addition, some places only have freeways on one side, meaning the side that doesn't get lights gets less lighting.

Do you guys know why they might do this?

Here's some examples:

DVP, one side only:


Highway 404, two sides:


Gardiner Expy, two sides:



Compared to a standard median high-mast-lighting.

[ErmineNotyours]

WA-18 in Federal Way.  There's no median to speak of to put these lights in, so they're a side-order.

At the other end of 18 by I-90.  Mixed center and side lights.  These lights have been cut down to two elements per mast.

[Great Lakes Roads]

The Dan Ryan (I-90/94), Kingery (I-80/94), Stevenson (I-55) between LSD and I-294, and I-57 south of I-80 in Chicago have high-mast lighting on the sides of the freeway.

Example:
https://www.google.com/maps/@41.7242944,-87.6242867,3a,75y,350.24h,93.5t/data=!3m6!1e1!3m4!1scfZ7cKRVhRI_VVjEnfTkWw!2e0!7i16384!8i8192

[tdindy88]

I-70 on the east side of Indianapolis between I-65 and I-465 mainly features this kind of lighting.

[RobbieL2415]

I-84 in East Hartford is lit with field lights from Exit 57-54.
https://www.google.com/maps/@41.7645473,-72.6463764,3a,75y,111.63h,84.38t/data=!3m6!1e1!3m4!1s90y2-6Zkm8xSaCeQuR3urA!2e0!7i16384!8i8192

...and again before ending at I-90.
https://www.google.com/maps/@42.1163047,-72.0752444,3a,75y,47.82h,97.17t/data=!3m7!1e1!3m5!1scRW9J742zv7r3rFSB5_3KQ!2e0!6shttps:%2F%2Fstreetviewpixels-pa.googleapis.com%2Fv1%2Fthumbnail%3Fpanoid%3DcRW9J742zv7r3rFSB5_3KQ%26cb_client%3Dmaps_sv.tactile.gps%26w%3D203%26h%3D100%26yaw%3D294.0217%26pitch%3D0%26thumbfov%3D100!7i16384!8i8192

[Occidental Tourist]

They put high mast lighting in both the median and on the sides of selected parts of the CA-91/I-5 interchange near Anaheim, California.



The ones in background on the right side of the picture are near where the 5 south to 91 east ramp touches down (east side of the interchange) and there is a residential neighborhood there in the acute angle made up by the 5 and 91.  The homes are from the 50s and the high mast lights went in in the 90s when the interchange was rebuilt. I would have been angry if I'd lived in that neighborhood at that time because they are pretty bright.

[plain]

WA-18 in Federal Way.  There's no median to speak of to put these lights in, so they're a side-order.

At the other end of 18 by I-90.  Mixed center and side lights.  These lights have been cut down to two elements per mast.

You hit the nail right on the head with this.

The main reason why an agency wouldn't place them in the median is simply because there's no room for them. The mast for this type of lightning gets pretty big at its base. Look at I-95 through Baltimore (city) and notice how wide the median is there (basically 2 Jersey Barriers with rocks filled in between). Median-mounted high masts works there. If it just had a single standard Jersey Barrier then it wouldn't work and would've been mounted on the side(s) instead.

Also, many interchanges would have them side mounted, regardless of median width.

[Revive 755]

The Dan Ryan (I-90/94), Kingery (I-80/94), Stevenson (I-55) between LSD and I-294, and I-57 south of I-80 in Chicago have high-mast lighting on the sides of the freeway.

Example:
https://www.google.com/maps/@41.7242944,-87.6242867,3a,75y,350.24h,93.5t/data=!3m6!1e1!3m4!1scfZ7cKRVhRI_VVjEnfTkWw!2e0!7i16384!8i8192

I-290 through Schaumburg has high-mast lighting on the sides as well.

[jeffandnicole]

Many transportation departments are doing away with them specifically for the reason you mention - wasted light.

[Mdcastle]

MnDOT doesn't put high mast lights in medians unless there's no space on the sides. The ones used for long stretches of freeway, as opposed to interchanges, have a "Medium Assymetric" distribution similar to ordinary cobrahead fixtures- most of the light thrown towards the road and then to either side.

[amroad17]

I-275, Northern Kentucky...
https://goo.gl/maps/sRnJxNfpjHkqzbP98
https://goo.gl/maps/yea3Eb1V7HtLfeJG6

[SkyPesos]

I-270 at the I-670 interchange have them on the sides and in the median. Some more side placed ones a bit north on I-270 at the OH 161 interchange.

[cbeach40]

Ontario, Highway 401 at the Highway 403 interchange (one side) and between Exeter Road and Highway 402 (both sides).

In both cases the HML was done as a retrofit on an exiting highway. Putting the HML foundations in the median would have required the storm sewers running along the median to be extensively reconfigured, so this option was selected instead.

[Henry]

The Dan Ryan (I-90/94), Kingery (I-80/94), Stevenson (I-55) between LSD and I-294, and I-57 south of I-80 in Chicago have high-mast lighting on the sides of the freeway.

Example:
https://www.google.com/maps/@41.7242944,-87.6242867,3a,75y,350.24h,93.5t/data=!3m6!1e1!3m4!1scfZ7cKRVhRI_VVjEnfTkWw!2e0!7i16384!8i8192

You see a lot of them in Houston too:

https://www.google.com/maps/@29.7741579,-95.3231348,3a,15y,241.71h,98.86t/data=!3m6!1e1!3m4!1sZir1r4CABRVQ0IwPckBN1A!2e0!7i16384!8i8192

Literally every freeway down there has them!

[roadfro]

Ontario, Highway 401 at the Highway 403 interchange (one side) and between Exeter Road and Highway 402 (both sides).

In both cases the HML was done as a retrofit on an exiting highway. Putting the HML foundations in the median would have required the storm sewers running along the median to be extensively reconfigured, so this option was selected instead.

I'd guess that this is the main answer for the whole thread. If a DOT decided to install high mast lighting along a freeway that didn't have it before, and assuming this isn't part of a larger reconstruction project, it's likely much easier to install lighting along the outside edges. You have to think about both minor foundation work and trenching the electrical lines.

If there's adequate inside shoulder space, retrofitting HML into an existing jersey wall isn't really a space consideration–as can be seen in this street view example in Las Vegas, the width of a jersey wall to support HML structure just about doubles, whereas a sign structure base is a bit wider. The expense comes if future HML wasn't accounted for in initial designs, because you have to trench electrical out to the median and rebuild the jersey wall at each HML location...a big expense, compounded by the traffic control needed to close lanes while you do that. If you install the lighting on the side, you can do all the work off the side of the road with minimal traffic control and disruption–even if it might cost more to run electrical for lighting on both sides of the highway, the cost of installation and not having to rebuild parts of the median is likely less overall.

[Henry]

Ontario, Highway 401 at the Highway 403 interchange (one side) and between Exeter Road and Highway 402 (both sides).

In both cases the HML was done as a retrofit on an exiting highway. Putting the HML foundations in the median would have required the storm sewers running along the median to be extensively reconfigured, so this option was selected instead.

I'd guess that this is the main answer for the whole thread. If a DOT decided to install high mast lighting along a freeway that didn't have it before, and assuming this isn't part of a larger reconstruction project, it's likely much easier to install lighting along the outside edges. You have to think about both minor foundation work and trenching the electrical lines.

If there's adequate inside shoulder space, retrofitting HML into an existing jersey wall isn't really a space consideration–as can be seen in this street view example in Las Vegas, the width of a jersey wall to support HML structure just about doubles, whereas a sign structure base is a bit wider. The expense comes if future HML wasn't accounted for in initial designs, because you have to trench electrical out to the median and rebuild the jersey wall at each HML location...a big expense, compounded by the traffic control needed to close lanes while you do that. If you install the lighting on the side, you can do all the work off the side of the road with minimal traffic control and disruption–even if it might cost more to run electrical for lighting on both sides of the highway, the cost of installation and not having to rebuild parts of the median is likely less overall.

What about when the replacement HMLs are off to the side instead of in the median where conventional cobra head streetlights were before? (Any Houston freeway or the northern end of the Downtown Connector in Atlanta should come to mind.) I think they'd tear out the old jersey barrier and remove the electrical components there, since the median lights are no longer there. Perhaps there's more to that, is there not?

[Bitmapped]

Ontario, Highway 401 at the Highway 403 interchange (one side) and between Exeter Road and Highway 402 (both sides).

In both cases the HML was done as a retrofit on an exiting highway. Putting the HML foundations in the median would have required the storm sewers running along the median to be extensively reconfigured, so this option was selected instead.

I'd guess that this is the main answer for the whole thread. If a DOT decided to install high mast lighting along a freeway that didn't have it before, and assuming this isn't part of a larger reconstruction project, it's likely much easier to install lighting along the outside edges. You have to think about both minor foundation work and trenching the electrical lines.

If there's adequate inside shoulder space, retrofitting HML into an existing jersey wall isn't really a space consideration–as can be seen in this street view example in Las Vegas, the width of a jersey wall to support HML structure just about doubles, whereas a sign structure base is a bit wider. The expense comes if future HML wasn't accounted for in initial designs, because you have to trench electrical out to the median and rebuild the jersey wall at each HML location...a big expense, compounded by the traffic control needed to close lanes while you do that. If you install the lighting on the side, you can do all the work off the side of the road with minimal traffic control and disruption–even if it might cost more to run electrical for lighting on both sides of the highway, the cost of installation and not having to rebuild parts of the median is likely less overall.

What about when the replacement HMLs are off to the side instead of in the median where conventional cobra head streetlights were before? (Any Houston freeway or the northern end of the Downtown Connector in Atlanta should come to mind.) I think they'd tear out the old jersey barrier and remove the electrical components there, since the median lights are no longer there. Perhaps there's more to that, is there not?

I can't imagine that any agency would rip out existing median barrier just because they eliminated median lights. Concrete barriers are extremely expensive to construct. What is normally done is to remove the light fixtures down to their base, and if there are holes in the concrete barrier, to fill them in with concrete or plate them over.

[CoreySamson]

Yeah as Henry said, Houston and surrounding areas do this a lot (mostly because we don't really have grassy medians to begin with):

US-59 in Shepherd:
TX-288 in Clute:
TX-288 in Houston:
I-10 in Channelview:

[roadfro]

Another potential reason for the side HML is that it might be much easier for maintenance. When replacing lights or what have you, it might be better for DOT crews to be on the right shoulder (perhaps fully off the pavement) as opposed to parked in the left shoulder or left lane (and need to do a short-term lane closure during maintenance activity).

Yeah as Henry said, Houston and surrounding areas do this a lot (mostly because we don't really have grassy medians to begin with):

US-59 in Shepherd:
TX-288 in Clute:
TX-288 in Houston:
I-10 in Channelview:

He says as two of the examples show grassy medians...    But I get what you mean.