Most abrupt change from rural to urban/suburban?

[pumpkineater2]

(the built-upon areas are water-tight -- those which are not are perhaps not as safe?).

The not built upon places are prone to flooding, as they are not protected by the levees, which in this case, is the reason for such an abrupt change between a rural and suburban setting.

[vtk]

US 23, I-75, or any road between, crossing the Ohio—Michigan border.

[triplemultiplex]

WB I-80 coming into Salt Lake City is quite abrupt. Yeah there's some McMansions in the mountains between there and Park City, but once you come into the valley it's a real city splayed out in front of you.  Same effect WB I-40 into Albuquerque.  The mountains limit the sprawl so once you hit some flat land, the city just erupts.

[DandyDan]

For me, it's going eastbound on I-80 from Lincoln to Omaha.  It's rolling farmland and then suddenly at  the NE 370 exit, it suddenly turns into suburban Omaha.  Going east across the Mormon Bridge on I-680 or north from Council Bluffs on I-29 into rural Pottawattomie County Iowa can be jarringly sudden, too.  Going south on I-29 from Council Bluffs used to feel like that, too, but they've put in some industrial developments along that road and I think eventually, that area will feel like you're driving through an industrial park.

[TXtoNJ]

I think I-10 entering New Orleans takes the cake
https://goo.gl/maps/ktiVC9fUs512

That seems to be a theme in NOLA -- abrupt cut-offs in suburban developments. Though there's some obvious logic to this (the built-upon areas are water-tight -- those which are not are perhaps not as safe?).

The land that the suburbs were built upon is drained swamp, surrounded by levees as mentioned upthread. The cost of development is too high unless all the drained land is going to be used intensively.

[TEG24601]

I-90...
Westbound - You come out of the mountains, down from Snoqualmie Pass (at 80+), around a bend, and BOOM, you have entered Issaquah, more traffic, slower speed limit, and HOV lanes.


I-5...
Northbound - Tooling around at 70, with a large median (it may be paved, but it counts) surrounded by trees, then you go under the exit for the airport, and suddenly you have more lanes, a concrete roadway, lots of lighting, more traffic, and a 60MPH Speed Limit.

[jakeroot]

I think I-10 entering New Orleans takes the cake
https://goo.gl/maps/ktiVC9fUs512

That seems to be a theme in NOLA -- abrupt cut-offs in suburban developments. Though there's some obvious logic to this (the built-upon areas are water-tight -- those which are not are perhaps not as safe?).

The land that the suburbs were built upon is drained swamp, surrounded by levees as mentioned upthread. The cost of development is too high unless all the drained land is going to be used intensively.

Perhaps that explains why New Orleans felt like such a large city the last time I was there.

[SP Cook]

To the extent that it can be called "urban", Charleston, WV, as it is approached from I-79.  No sububs visable and no real increase in traffic as 79 ends and merges into 77, and then, within 2 miles you are in the middle of downtown.   

Also, to the extent it can be called "urban", Myrtle Beach as it is approached on the Conway Bypass.  Nothing but pine scrubs and then the road ends in the middle of the built up area.

But I would go with the Everglades.

[Mr_Northside]

Pittsburgh. It doesn't seem like much...until you get through the tunnel or (if from the north) near the end of the valley.

I don't know if I agree much with the tunnel part.  Most of the Parkways East & West are pretty suburban on the non-downtown sides of the tunnels, so no abrupt change from a rural setting in those instances (IMO)
I guess I-279 fits the topic.  It has pretty rural feel all the way to Bellevue/West View and changes pretty quickly is it crests Summer Hill and descends toward downtown.
If you don't consider an airport making an area any less rural, I-376 feels pretty rural coming south from Beaver County, and right after the south junction with Business-376 you're in the whole Moon/Robinson strip mall mess fairly abruptly.

[doorknob60]

Another one is I-84 east of Boise: https://www.google.com/maps/@43.5420969,-116.1064365,14725m/data=!3m1!1e3

To the west of Boise there is a lot of suburbs and farmland, head east, and it's instantly nothing.

[WillWeaverRVA]

US 360 in southwestern Chesterfield County for me.  It has been built out farther past Winterpock Road(SR 621) and Woodlake Village Pkwy as the years have gone on, but it astonishes me how heading eastbound the road goes from 4 lanes to 8 lanes in less than 2 miles.

US 250 in Henrico/Goochland Counties is pretty much the same way. It's basically sprawl all the way out to VA 288, then suddenly farmland.

VA 5 leaving Richmond also counts.

[Buffaboy]

It's debatable, but I would say the South Grand Island Bridge, and the Peace Bridge near Buffalo.

Edit: Also the eastern edge of St. Catharines, ON.

[xcellntbuy]

Another two areas to consider are just about anywhere outside of Reno-Sparks, NV and metro Las Vegas, NV.

[Jardine]

Omaha/Papillion NE, 72nd street just south of Shadow Lake Mall (pretty big development, Best Buy grocery store, Kohls, etc) goes from 4 lane to county gravel road. Just like that.

(or it did last time I was there, might be paved now)

[cl94]

Omaha/Papillion NE, 72nd street just south of Shadow Lake Mall (pretty big development, Best Buy grocery store, Kohls, etc) goes from 4 lane to county gravel road. Just like that.

(or it did last time I was there, might be paved now)

Looking around that area, it seems to happen quite a bit, but not quite as extreme as that. Then again, I don't think much will beat I-229 before the road at its northern terminus was paved in 2006.

[jwolfer]

I was thinking the Everglades.

Definitely agree, flying out of Miami at night the difference is even more apparant

[formulanone]

I was thinking the Everglades.

Definitely agree, flying out of Miami at night the difference is even more apparant

Everything to the top and right of this photo is the Everglades:

[

[wanderer2575]

Southbound US-127 entering East Lansing, Michigan.  You go through a slight curve to the right just before the exit to M-43 and POW! you are in the city.  There's development for a mile north but you don't really see it due to trees to the east and a sound wall to the west.

https://www.google.com/maps/@42.7429967,-84.5094277,1944m/data=!3m1!1e3

[jbnati27]

I-71 Northbound into Columbus is pretty abrupt. You're out in the middle of cornfields, hit the exit for Ohio 665 and then you're in the suburbs of Columbus all of the sudden.

[cl94]

I-71 Northbound into Columbus is pretty abrupt. You're out in the middle of cornfields, hit the exit for Ohio 665 and then you're in the suburbs of Columbus all of the sudden.

SB is less, but not much different. Speed limit goes to 70 immediately north of Exit 121, which has the area's second-largest retail development. There are residential developments, but you can't see anything from I-71 and the next exit is 10 miles away.

[tdindy88]

Might as well throw in I-70 heading east into Columbus. With the exception of the fact that the highway is six lanes all the way from Springfield (and soon Dayton) there is a pretty definitive change as one gets within one mile of the Hillard-New Rome interchange just west of I-270. Trees do line the road as you near the exit but there's about a two-mile window from which the highway turns from rural agricultural land to a developed area leading toward the city. I think zoning has to do with the reason that western Franklin County is still rural and the abrupt cutoff in development is for a reason.

[SD Mapman]

Omaha/Papillion NE, 72nd street just south of Shadow Lake Mall (pretty big development, Best Buy grocery store, Kohls, etc) goes from 4 lane to county gravel road. Just like that.

(or it did last time I was there, might be paved now)

Looking around that area, it seems to happen quite a bit, but not quite as extreme as that. Then again, I don't think much will beat I-229 before the road at its northern terminus was paved in 2006.

Sioux Falls still has a four-lane road with not much development transition into a gravel road (Benson Road)... but that might be gone in the next few years (if not already).

[cl94]

Omaha/Papillion NE, 72nd street just south of Shadow Lake Mall (pretty big development, Best Buy grocery store, Kohls, etc) goes from 4 lane to county gravel road. Just like that.

(or it did last time I was there, might be paved now)

Looking around that area, it seems to happen quite a bit, but not quite as extreme as that. Then again, I don't think much will beat I-229 before the road at its northern terminus was paved in 2006.

Sioux Falls still has a four-lane road with not much development transition into a gravel road (Benson Road)... but that might be gone in the next few years (if not already).

It still does. Transition zone from 5 lanes to gravel is under 500 feet.

[vtk]

Might as well throw in I-70 heading east into Columbus. With the exception of the fact that the highway is six lanes all the way from Springfield (and soon Dayton) there is a pretty definitive change as one gets within one mile of the Hillard-New Rome interchange just west of I-270. Trees do line the road as you near the exit but there's about a two-mile window from which the highway turns from rural agricultural land to a developed area leading toward the city. I think zoning has to do with the reason that western Franklin County is still rural and the abrupt cutoff in development is for a reason.

Yes, development within the Big Darby Creek watershed became very difficult (in some townships more than others) after that waterway's exceptional biological diversity was publicized in the late 20th century.  Little agreement has been reached regarding how much development can be allowed without threatening the creek too much.  Without a plan to follow, only a few super-low-density residential "developments" have sprung up.

[UNDSIOUX]

Pittsburgh. It doesn't seem like much...until you get through the tunnel or (if from the north) near the end of the valley.

I don't know if I agree much with the tunnel part.  Most of the Parkways East & West are pretty suburban on the non-downtown sides of the tunnels, so no abrupt change from a rural setting in those instances (IMO)
I guess I-279 fits the topic.  It has pretty rural feel all the way to Bellevue/West View and changes pretty quickly is it crests Summer Hill and descends toward downtown.
If you don't consider an airport making an area any less rural, I-376 feels pretty rural coming south from Beaver County, and right after the south junction with Business-376 you're in the whole Moon/Robinson strip mall mess fairly abruptly.

The first thing I thought of when I saw this topic was approaching Pittsburgh on the Parkway West.  When I visited a few years back, I was amazed driving in from the airport area how heavily forested this stretch of road is and that there is little sign of the suburban sprawl (sans the Robinson Towne Center area) or urban build-up that you see in most metro areas.  The freeway is mostly only two lanes each way (due to the tunnels), and to the outsider, it appears to the naked eye to be semi-rural, though it may not be.  If I had not known where I was, there is no way you could have convinced me that the city core for a metropolitan area of approximately 2 million people was over that "hill" when entering the Fort Pitt tunnels.  I think that is what makes the whole Ft. Pitt Tunnel experience so interesting- going from "country" to "city" just like that. 

Also, I was amazed at the small towns that existed only 15-20 miles from the downtown with large expanses of forested land between them.  When I also passed Pittsburgh to the west on I-79 a few years later, there also seemed to very little sign IMO that we were just west of a major city.  I have found no other city like Pittsburgh in my travels and I find it hard to describe to others (especially here in the Midwest where there is very little terrainwise to slow sprawl) how Pittsburgh is laid out.

Honorable mentions:  Indianapolis from I-65 coming in from the northwest.  This has changed a little bit with the growth of Zionsville and the widening between Lebanon and 865, but I was always amazed that it was quiet and rural up until you hit I-465 and then... bam- here's Indianapolis.  Was the same way on I-74 both west and east of town until the last few years.

Chattanooga coming in from I-24 west of town- this is mostly due to terrain and Lookout Mountain, but I-24 is just a freeway winding through valleys, you get next to the river and then you hit that curve, and downtown Chattanooga is right there.  The only way you know you are getting close is the awful stop-and-go traffic that can occur in that area....

Winnipeg from any where coming from the south on 100 (Perimeter Highway)- when I first visited Winnipeg, we were driving around the city and I wondered why they needed to build such a bypass considering it looked like North Dakota around it (flat farmland for miles with no subdivisions or commercial buildings).  Once you turn off the Perimeter Highway on 1 or 75, you realize there is a dense city all the way up to the downtown core.

Grand Rapids from I-196- my memory is fuzzy, but it was pretty quiet heading into GRR from the west until you hit that hill going down into the downtown area.

Agreements with other comments- I-24 entering Murfreesboro/suburban Nashville (though that ugly sprawl continues for miles and miles after that),  Seattle (again a lot to do with the trees blocking the strip malls and sprawl usually visible from the freeways in other cities)