# What is the function of cameras along expressways?
**URL:** https://boards.straightdope.com/t/what-is-the-function-of-cameras-along-expressways/838908
**Category:** Factual Questions
**Created:** [August 19, 2019, 9:46pm UTC](https://boards.straightdope.com/t/what-is-the-function-of-cameras-along-expressways/838908 "2019-08-19T21:46:05Z")
**Posts on this page:** 14
**Page:** 1
### Author:  [@Dinsdale](https://boards.straightdope.com/u/Dinsdale)
#### Post date: [August 19, 2019, 9:46pm UTC](https://boards.straightdope.com/t/what-is-the-function-of-cameras-along-expressways/838908/1 "2019-08-19T21:46:05Z")
Just got back from driving from Michigan to Chicago along 80/90 around the bottom of Lake Michigan. Through Indiana, we noticed a specific sort of antenna array. Far more frequently than one per mile, there was an antenna approximately 30 feet tall, with one or two domed security cameras near the top.
(Near the top, they also had a small rectangular metal box, connected to the ground with 4 large metal conduits. Around the base, was a chain-link/barbed wire fence, with a small metal control box. The fence had a sign saying something like “authorized personnel only.”)
When we transitioned to 294 - the Tristate tollway, single cameras were mounted on cylindrical posts.
Sure, we can post this in IMHO/MPSIMS and get all manner of theories as to who installs/maintains/uses these for what purposes, but I wondered if anyone might actually know?
I would imagine that one use would be to monitor travel conditions. If so, they did a crappy job of it. Around mile 17, there was an electronic sign that said 15 minutes to the border. At mile 12, we came to a complete stop. Took at least 30 minutes to cover the next 4 miles due to a pretty serious looking accident. I think the fact that we were moving so slow contributed to my noticing all of the identical antennae!
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### Author:  [@beowulff](https://boards.straightdope.com/u/beowulff)
#### Post date: [August 19, 2019, 10:05pm UTC](https://boards.straightdope.com/t/what-is-the-function-of-cameras-along-expressways/838908/2 "2019-08-19T22:05:58Z")
Well, out here, you can go to the DPS [website](https://www.az511.gov/cctv?start=0&length=10&order%5Bi%5D=2&order%5Bdir%5D=asc) and view the traffic in realtime.
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### Author:  [@Bone](https://boards.straightdope.com/u/Bone)
#### Post date: [August 19, 2019, 10:26pm UTC](https://boards.straightdope.com/t/what-is-the-function-of-cameras-along-expressways/838908/3 "2019-08-19T22:26:01Z")
Could they be ALPRs (Automated licence plate readers)? Some highway systems in our area has them, they capture every vehicle license plate that goes across the highway. They will also compare license plates to any with outstanding warrants, or other things that might warrant a rapid response, and auto communicate with whatever nearby law enforcement officer is in the area so they can make the stop.
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### Author:  [@Sicks\_Ate](https://boards.straightdope.com/u/Sicks_Ate)
#### Post date: [August 19, 2019, 11:54pm UTC](https://boards.straightdope.com/t/what-is-the-function-of-cameras-along-expressways/838908/4 "2019-08-19T23:54:08Z")
LPR and/or traffic monitoring.
I’ll go for the latter, since having that many LPR would be overkill.
ETA: Not sure about Indiana, but some states have sensors that measure road surface temperature and precip/ice buildup. Could be especially useful around the Great Lakes.
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### Author:  [@Dinsdale](https://boards.straightdope.com/u/Dinsdale)
#### Post date: [August 20, 2019, 12:10am UTC](https://boards.straightdope.com/t/what-is-the-function-of-cameras-along-expressways/838908/5 "2019-08-20T00:10:24Z")
One thing that is crazy about that stretch of road is that traffic ALWAYS sucks there. I was actually THRILLED to see a couple of banged up cars at the end of the jam, as it usually just opens up with no sign of why it stopped.
But we were listening to local radio while stuck in the jam, and “traffic on the 8s” made no mention of us.
If they were for drivers to use - maybe when planning travel or something, I would think they would have some kind of signs like, “Check [Trafficcam.com](http://Trafficcam.com)”
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### Author:  [@jnglmassiv](https://boards.straightdope.com/u/jnglmassiv)
#### Post date: [August 20, 2019, 1:11am UTC](https://boards.straightdope.com/t/what-is-the-function-of-cameras-along-expressways/838908/6 "2019-08-20T01:11:40Z")
> [@Dinsdale](#):
>
> But we were listening to local radio while stuck in the jam, and “traffic on the 8s” made no mention of us.
Excuse me, that’s ‘traffic and wedder togedder on the eights.’
You can see some of the Chicago area cam images locally here:
> **[Travel Midwest](https://www.travelmidwest.com/map/chicagoArea)**
>
> Travel Midwest
Make sure the Cameras icon is enabled and zoom in, they’re a little difficult to find.
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### Author:  [@Voyager](https://boards.straightdope.com/u/Voyager)
#### Post date: [August 20, 2019, 2:02am UTC](https://boards.straightdope.com/t/what-is-the-function-of-cameras-along-expressways/838908/7 "2019-08-20T02:02:21Z")
The ones in the Bay Area are for traffic monitoring. The signs giving travel times are usually pretty accurate.
Traffic on the 8s is not much indication of anything. If they have a chopper someplace they’ll report about that problem ad nauseum while ignoring the rest. My commute included a stretch which was usually awful, but they reported on bridges near San Francisco, even if they were clear.
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### Author:  [@Spiderman](https://boards.straightdope.com/u/Spiderman)
#### Post date: [August 20, 2019, 6:22am UTC](https://boards.straightdope.com/t/what-is-the-function-of-cameras-along-expressways/838908/8 "2019-08-20T06:22:59Z")
> [@Bone](#):
>
> Could they be ALPRs (Automated licence plate readers)? Some highway systems in our area has them, they capture every vehicle license plate that goes across the highway.
30’ up would not be an ideal angle to capture a plate, especially in a car where it ‘hangs’ under a bumper. I’d say traffic flow cams.
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### Author:  [@Broomstick](https://boards.straightdope.com/u/Broomstick)
#### Post date: [August 20, 2019, 6:53am UTC](https://boards.straightdope.com/t/what-is-the-function-of-cameras-along-expressways/838908/9 "2019-08-20T06:53:28Z")
> [@Dinsdale](#):
>
> One thing that is crazy about that stretch of road is that traffic ALWAYS sucks there. I was actually THRILLED to see a couple of banged up cars at the end of the jam, as it usually just opens up with no sign of why it stopped.
Yep, that’s why sometimes I’ll take the local roads. Sure, the \*posted \*speed is slower, but sometimes it’s actually faster than the real speed on the freeways. But that’s not a practical option for tourists passing through on their way to somewhere else. People think I’m nuts for often avoiding the freeways around here, but as you note, the traffic is _always_ horrible.
> [@](#):
>
> But we were listening to local radio while stuck in the jam, and “traffic on the 8s” made no mention of us.
The “traffic on the 8’s” station is out of Chicago, which treats the Indiana suburbs as unloved red-headed stepchildren. You need to listen to an Indiana station going through there, of which there are few. I usually use 105.5 which is good with traffic in Lake and Porter counties. It is also a country music station, which may or may not be a problem depending on how you view that genre.
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### Author:  [@Dinsdale](https://boards.straightdope.com/u/Dinsdale)
#### Post date: [August 20, 2019, 12:43pm UTC](https://boards.straightdope.com/t/what-is-the-function-of-cameras-along-expressways/838908/10 "2019-08-20T12:43:19Z")
> [@Broomstick](#):
>
> Yep, that’s why sometimes I’ll take the local roads. …
Yeah - I used to live/work in Valpo, and have often wondered about going S to 30. Not as familiar w/ the other more local roads as to which go through. But every 5th time or so, you’ll cruise right through, and think, “Hey, maybe they licked the problem!” :smack:
Thought we had beat it by hitting that section around 11 a.m., but no such luck. Earlier this summer, I hit that stretch with the signs again saying approx. a mile-a-minute to the border. Took an hour to make the last 8 miles…
We’re heading up to the dunes later this week - I’ll see if I can snap a couple of photos of the antennae/cameras. They impress me as pretty substantial installations. And I’ll keep track of roughly how many there are. I’d wager there were at least 2 per mile (it actually seemed more like 3-4.)
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### Author:  [@MikeF](https://boards.straightdope.com/u/MikeF)
#### Post date: [August 20, 2019, 1:07pm UTC](https://boards.straightdope.com/t/what-is-the-function-of-cameras-along-expressways/838908/11 "2019-08-20T13:07:39Z")
So, remind me how the monitors work that determine the speed of traffic, As in “Route 1 - 12 miles. Travel time - 17 minutes”
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### Author:  [@CookingWithGas](https://boards.straightdope.com/u/CookingWithGas)
#### Post date: [August 20, 2019, 1:47pm UTC](https://boards.straightdope.com/t/what-is-the-function-of-cameras-along-expressways/838908/12 "2019-08-20T13:47:03Z")
This is specific to Indiana, although I am not sure if these cameras are on the exact route you traveled. Click on the “Camera” checkbox and you can view the camera feeds real-time.
> **[INDOT Trafficwise](https://511in.org/pws/)**
>
> Reports regarding traffic incidents, winter road conditions, traffic cameras, active and planned construction, etc.
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### Author:  [@Dinsdale](https://boards.straightdope.com/u/Dinsdale)
#### Post date: [August 20, 2019, 3:54pm UTC](https://boards.straightdope.com/t/what-is-the-function-of-cameras-along-expressways/838908/13 "2019-08-20T15:54:36Z")
> [@CookingWithGas](#):
>
> This is specific to Indiana, although I am not sure if these cameras are on the exact route you traveled. Click on the “Camera” checkbox and you can view the camera feeds real-time.
>
> [INDOT Trafficwise](http://pws.trafficwise.org/pws/)
That is exactly it. If you click on NW IN, it shows the cameras along the route I describe, along w/ the location of travel time and other traffic info signs. You can see how many of them there are. Thanks.
I guess I need to figure out how we can access this on our phones to see if an alternate route is called for. Next time, I’ll try to pay attention to see if it is advertised anywhere on signs or at rest stops.
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### Author:  [@Mr\_Downtown](https://boards.straightdope.com/u/Mr_Downtown)
#### Post date: [August 21, 2019, 4:11am UTC](https://boards.straightdope.com/t/what-is-the-function-of-cameras-along-expressways/838908/14 "2019-08-21T04:11:25Z")
I believe the official clearinghouse for traffic info in the Greater Chicago Region is [Travel Midwest.](https://travelmidwest.com/lmiga/home.jsp) Their home page now displays a live map that should be the result of the various monitored cameras and pavement sensors in the region’s expressway network.
I believe both Google (perhaps through Waze) and Here have entire divisions devoted to realtime traffic info that can be displayed on your smartphones. I no longer have a car, so these modern developments are still largely theoretical to me.