Signs to mark time zone boundaries?

[JayhawkCO]

I don't know that I've crossed a boundary on an interstate and NOT seen a sign posted.

When my wife and I drove to St. Louis in 2017, we didn't see any that WERE posted. Drove out via I-64 and drove home via I-70 (well, as far as Columbus before heading northeast to Canton, but there are no time zone boundaries by that point). I recall the car's clock changing when we crossed the Illinois–Indiana state line.

It's been a little while since I've crossed the Illinois/Indiana border, but yeah, I don't remember seeing one on I-80/I-94 back in 2021, which maybe makes sense since it's in Chicagoland. The rural crossings I think have been 18 years or so since I've been there.

[WillWeaverRVA]

There is an Atlantic Time Zone sign on I-95 just before the Canadian border.

[jmacswimmer]

I recall a Pacific Time Zone sign on I-11/US 93 entering Nevada, but not on US 93 entering Arizona. Although of course, there is no time change here approximately 8 months out of the year.

I was told some time ago that the Navajo reservation in northeast Arizona does observe DST -- is this still true?  That might complicate any attempt to sign DST info on highways that cross the reservation (including I-40).

Yes, and then there is Hopi territory inside the Navajo reservation that does not observe DST.

There wasn't much cell service in that whole area, at least not on AZ-264 and the road through Pinon, so I don't know what my clocks were showing, or if they would have shown any detail like that.

I remember my wife's phone was constantly bouncing back & forth during the drive from the Grand Canyon to Page via AZ 64 & US 89. Mine briefly went forward an hour at the Desert View Watchtower just inside the Grand Canyon east entrance, but then mostly stayed on MST on the way to Page unlike my wife's.

When we did a tour of Antelope Canyon (run by the Navajo) I remember the ticket pdf's clarifying that the tour times were based on Page local time (MST) and warning that phones may bounce back & forth depending on carrier/tower/etc. And during that tour, both of our phones were constantly bouncing back & forth. My phone also went forward to MDT and stayed forward at the Glen Canyon Dam, but that could also be related to the proximity of the Utah line at that point.

[GaryA]

I recall a Pacific Time Zone sign on I-11/US 93 entering Nevada, but not on US 93 entering Arizona. Although of course, there is no time change here approximately 8 months out of the year.

The Hoover Dam (which carried US 93 traffic for many years) has clocks labelled "Nevada Time" and "Arizona Time".

[Rothman]

I don't know that I've crossed a boundary on an interstate and NOT seen a sign posted.

When my wife and I drove to St. Louis in 2017, we didn't see any that WERE posted. Drove out via I-64 and drove home via I-70 (well, as far as Columbus before heading northeast to Canton, but there are no time zone boundaries by that point). I recall the car's clock changing when we crossed the Illinois–Indiana state line.

It's been a little while since I've crossed the Illinois/Indiana border, but yeah, I don't remember seeing one on I-80/I-94 back in 2021, which maybe makes sense since it's in Chicagoland. The rural crossings I think have been 18 years or so since I've been there.

Hm.  Could have sworn there was one out there somewhere coming from the east.  I'll see on Wednesday...

[NWI_Irish96]

I don't know that I've crossed a boundary on an interstate and NOT seen a sign posted.

When my wife and I drove to St. Louis in 2017, we didn't see any that WERE posted. Drove out via I-64 and drove home via I-70 (well, as far as Columbus before heading northeast to Canton, but there are no time zone boundaries by that point). I recall the car's clock changing when we crossed the Illinois–Indiana state line.

It's been a little while since I've crossed the Illinois/Indiana border, but yeah, I don't remember seeing one on I-80/I-94 back in 2021, which maybe makes sense since it's in Chicagoland. The rural crossings I think have been 18 years or so since I've been there.

Hm.  Could have sworn there was one out there somewhere coming from the east.  I'll see on Wednesday...

The IL/IN border on I-80/94 isn't a time zone boundary, so it would be really weird if you ever saw a sign there. The time zone boundary on I-80 is at the LaPorte/St Joseph county line and is marked. The time zone boundary on I-94 is at the IN/MI state line and is marked.

[hbelkins]

Kentucky signs time zone boundaries on interstates and parkways, and on some surface (state and US) routes as well.

[Rothman]

I don't know that I've crossed a boundary on an interstate and NOT seen a sign posted.

When my wife and I drove to St. Louis in 2017, we didn't see any that WERE posted. Drove out via I-64 and drove home via I-70 (well, as far as Columbus before heading northeast to Canton, but there are no time zone boundaries by that point). I recall the car's clock changing when we crossed the Illinois–Indiana state line.

It's been a little while since I've crossed the Illinois/Indiana border, but yeah, I don't remember seeing one on I-80/I-94 back in 2021, which maybe makes sense since it's in Chicagoland. The rural crossings I think have been 18 years or so since I've been there.

Hm.  Could have sworn there was one out there somewhere coming from the east.  I'll see on Wednesday...

The IL/IN border on I-80/94 isn't a time zone boundary, so it would be really weird if you ever saw a sign there. The time zone boundary on I-80 is at the LaPorte/St Joseph county line and is marked. The time zone boundary on I-94 is at the IN/MI state line and is marked.

Ah, so my memory hasn't failed me.  Knew there was a sign out there.

[Big John]

I-24 crossing into Tennessee from Georgia looking west

There is a sign in the other direction, but is significantly covered by foliage.

[jmacswimmer]

I recall a Pacific Time Zone sign on I-11/US 93 entering Nevada, but not on US 93 entering Arizona. Although of course, there is no time change here approximately 8 months out of the year.

The Hoover Dam (which carried US 93 traffic for many years) has clocks labelled "Nevada Time" and "Arizona Time".

I saw that when we visited a year ago, but since it was May the clocks were synced up. Would have been cooler if I had visited November-February when they are an hour apart but still a nice touch!

[elsmere241]

I recall a Pacific Time Zone sign on I-11/US 93 entering Nevada, but not on US 93 entering Arizona. Although of course, there is no time change here approximately 8 months out of the year.

The Hoover Dam (which carried US 93 traffic for many years) has clocks labelled "Nevada Time" and "Arizona Time".

I saw that when we visited a year ago, but since it was May the clocks were synced up. Would have been cooler if I had visited November-February when they are an hour apart but still a nice touch!

I remember coming through in August or September 1980, and the clocks were not synched.  We didn't know Arizona wasn't on DST until we got to our motel in Williams.

[doorknob60]

Almost every time I've driven between time zones, it's been signed. A fun one is US-95's southern and northern segments are in Pacific Time, but the middle section (spanning parts of Oregon and Idaho) is in Mountain Time.

Here's the crossing on US-95 in Central Idaho. Sometimes called "Time Zone Bridge".

GSV Link

Here's the crossing in SE Oregon:

GSV Link

[MikeTheActuary]

When US 80 crosses the Alabama/Georgia state line, Eastern Time is signed.  Central Time is not.

(Phenix City, across the river from Columbus, unofficially observes Eastern Time, despite officially being in Central.)

I have a recollection of, when living in Alabama 30 years ago, Central Time being signed one county in from the AL/GA state line on I-85.   However, I checked quickly on GSV this morning, and didn't see any signage.

[Flint1979]

This one is small so you would probably miss it with the larger Welcome to Pure Michigan sign spanning over the highway.
https://www.google.com/maps/@41.7601713,-86.7506351,3a,15y,15.73h,91.68t/data=!3m7!1e1!3m5!1sjI0ivgl7Y73k7-8bYVXgHA!2e0!6shttps:%2F%2Fstreetviewpixels-pa.googleapis.com%2Fv1%2Fthumbnail%3Fcb_client%3Dmaps_sv.tactile%26w%3D900%26h%3D600%26pitch%3D-1.6785918182818733%26panoid%3DjI0ivgl7Y73k7-8bYVXgHA%26yaw%3D15.732918939886986!7i16384!8i8192!5m1!1e1?entry=ttu&g_ep=EgoyMDI1MDYwMS4wIKXMDSoASAFQAw%3D%3D

The one going into Indiana stands out a little more.
https://www.google.com/maps/@41.7598872,-86.7514826,3a,15y,251.97h,92.56t/data=!3m7!1e1!3m5!1sgJeE8AAKp7xChG4Ck1EEBw!2e0!6shttps:%2F%2Fstreetviewpixels-pa.googleapis.com%2Fv1%2Fthumbnail%3Fcb_client%3Dmaps_sv.tactile%26w%3D900%26h%3D600%26pitch%3D-2.563975334586061%26panoid%3DgJeE8AAKp7xChG4Ck1EEBw%26yaw%3D251.972927562564!7i16384!8i8192!5m1!1e1?entry=ttu&g_ep=EgoyMDI1MDYwMS4wIKXMDSoASAFQAw%3D%3D

[mapman1071]

Almost every time I've driven between time zones, it's been signed. A fun one is US-95's southern and northern segments are in Pacific Time, but the middle section (spanning parts of Oregon and Idaho) is in Mountain Time.

Here's the crossing on US-95 in Central Idaho. Sometimes called "Time Zone Bridge".

GSV Link

Here's the crossing in SE Oregon:

GSV Link

The Southern section of US 95 is in Arizona from the I-10 Bridge at Ehrenberg, AZ to the Mexico Border at San Luis, AZ and is in the Mountain Time Zone (no DST)

[lepidopteran]

Now I'm wondering if there are any 3di's that cross time zone boundaries. If there are, there aren't many.

I-275 (OH-KY-IN) did at one time, and even that was "sort of".  For it used to be that Indiana did not honor Daylight Savings Time, so it matched Eastern time in the winter and Central time in the summer. Nowadays, the Hoosier State is steadily Eastern time, except for those few sections in the western part of the state that align with Central.

[newyooper]

When US 80 crosses the Alabama/Georgia state line, Eastern Time is signed.  Central Time is not.

(Phenix City, across the river from Columbus, unofficially observes Eastern Time, despite officially being in Central.)

I have a recollection of, when living in Alabama 30 years ago, Central Time being signed one county in from the AL/GA state line on I-85.  However, I checked quickly on GSV this morning, and didn't see any signage.

All of the counties in the Upper Peninsula of Michigan that border Wisconsin are on Central Time (the rest of the UP is Eastern time).  There are plenty of signs marking this change.

[Bruce]

A better view of the Time Zone Bridge on US 95 in Idaho (which I crossed two days ago):

[ran4sh]

I-24 crossing into Tennessee from Georgia looking west

To clarify, it isn't the state line that is the TZ line, but rather, the county line that is less than a mile inside the state (along I-24). Where I-24 crosses the TN/GA state line both states are in Eastern

[Molandfreak]

At the officially-designated boundary in Ontario on Highway 17. The same spot on Highway 11 has much less fanfare, probably due to lower traffic counts, but there is also much more to the story at that location: As Canada does not have an equivalent of the American Uniform Time Act of 1966, municipalities are free to choose whether or not to observe DST. The Township of Atikokan officially sets its time in the Eastern Time Zone and does not use DST, even though it is west of this point. Many of the unorganized areas surrounding Atikokan also follow Eastern Standard Time year-round, so this sign is technically inaccurate in practice.

[mrsman]

I recall a Pacific Time Zone sign on I-11/US 93 entering Nevada, but not on US 93 entering Arizona. Although of course, there is no time change here approximately 8 months out of the year.

The Hoover Dam (which carried US 93 traffic for many years) has clocks labelled "Nevada Time" and "Arizona Time".

These are iconic.

https://www.google.com/maps/@36.0165825,-114.7380595,3a,37.5y,43.17h,82.28t/data=!3m7!1e1!3m5!1scae754B25rCrKCcr6PpVvg!2e0!6shttps:%2F%2Fstreetviewpixels-pa.googleapis.com%2Fv1%2Fthumbnail%3Fcb_client%3Dmaps_sv.tactile%26w%3D900%26h%3D600%26pitch%3D7.717740215676031%26panoid%3Dcae754B25rCrKCcr6PpVvg%26yaw%3D43.16631571929349!7i13312!8i6656!5m1!1e1?entry=ttu&g_ep=EgoyMDI1MDYxMC4xIKXMDSoASAFQAw%3D%3D

https://www.google.com/maps/@36.0154866,-114.7368098,3a,37.5y,71.23h,84.18t/data=!3m7!1e1!3m5!1sS1rN7xupZ9FHASkseq0mGA!2e0!6shttps:%2F%2Fstreetviewpixels-pa.googleapis.com%2Fv1%2Fthumbnail%3Fcb_client%3Dmaps_sv.tactile%26w%3D900%26h%3D600%26pitch%3D5.816881471881715%26panoid%3DS1rN7xupZ9FHASkseq0mGA%26yaw%3D71.22795362493073!7i16384!8i8192!5m1!1e1?entry=ttu&g_ep=EgoyMDI1MDYxMC4xIKXMDSoASAFQAw%3D%3D

Putting clocks at time zone boundaries should be more common.