Lack of Warning for Hazardous Curves on Interstate Highways

[Brian556]

I've noticed this occurs quite frequently.
Curves on all other types of highways, whether they pose a hazard or not, get curve signs. Most get chevrons. Yet, on Interstates, where expectations of a safe road are higher, there are curves need warning but have none.

Example#1. On I-40 EB in or near Jackson, TN; there is a curve so bad that the 18-wheeler and SUV in front of me nearly lost control because of it. This situation appears to be a design flaw, as there appears to be no need for a substandard curve at this location. The only warning is two low-mounted chevrons. Curve with advisory speed signs are really needed.

Example #2: I-75 in northern Florida. I encountered two curves that were sharp enough to not feel safe at the 70 MPH speed limit. Because of large vehicles in other lanes, you really can't see far enough ahead to see if traffic is stopping.

The previous two examples were In rural areas. Due to the frequent use of cruise control In rural areas, these are more hazardous. Without cruise control, you are likely to naturally slow down to the safe speed without realizing it.

In addition to curve signs, delineators are really on these curves.

[cpzilliacus]

I-495 (Capital Beltway), Outer Loop, between Md. 97 (Georgia Avenue and Md. 185 (Connecticut Avenue) has a pretty sharp curve to the left at the bottom of a long downhill grade that should be signed better.

[talllguy]

It could be that DOTs are reactive rather than proactive. It took a fiery explosion which claimed the life of a tanker truck's driver for Md. SHA to install this flashing curve warning sign.

[Zeffy]

Looks like New Jersey uses more than enough signage to sign curves:


Credit goes to roadnut on Photobucket for this photo

Of course, this is on the I-295/I-76/NJ 42 interchange project, so I have no clue if these are temporary or if these will be staying.

[jeffandnicole]

Looks like New Jersey uses more than enough signage to sign curves:


Credit goes to roadnut on Photobucket for this photo

Of course, this is on the I-295/I-76/NJ 42 interchange project, so I have no clue if these are temporary or if these will be staying.

That's since been modified.  They removed some of the truck signs and put in regular chevrons.  Still, an overabundance of signage in the area.  From what I recall though, the signage remains, so I guess it's doing its job!

The entire ramp will be eliminated eventually, so they'll be there until the ramp is closed (which is several years down the line)

[hbelkins]

There's a curve on the Mountain Parkway in Wolfe County that has an advisory speed of 55 mph. The term locals use for it, and the term used in my office, is ... wait for it ... "The 55 MPH Curve."

Use that phrase, and everyone knows what you're talking about.

There are a number of curves on I-77 north of Charleston, and a handful on I-79 north of Charleston, that aren't warned, but I feel uncomfortable driving the 70 mph speed limit on.

[JREwing78]

It's not an issue I've encountered frequently, at least in the upper Midwest. When there's a curve that warrants signage (with or without an advisory speed), it tends to be well-marked.

[Jardine]

I've always thought the curve at the west end of the over the river portion of the I-480 Missouri River bridge at downtown Omaha Nebraska was quite sharp for a curve, on an Interstate, on a bridge.

But I don't like heights either, and that might be part of it.

[roadman65]

In the OP I noticed he mentioned I-75 in Northern Florida.  I am guessing he is talking about a curve in Pasco County just north of FL 52.  I rode that curve many times, and it is not safe at 70 mph, especially with the cruise control engaged.

I wrote FDOT about it, but they said it was not a big issue to warrant warning signs, but I feel it is.

[vdeane]

Future I-86 has many advisory speeds on the Quickway.  I-81 also has this: http://goo.gl/maps/S8mmc

[Revive 755]

*  WB I-80 in Nebraska between Omaha and Lincoln has a curve with chevrons before crossing the Platte River, but I'm not seeing any advance curve signs:  Streetview

[PurdueBill]

I-70 eastbound at Mount Comfort Road (east of Indy) has curve warning sign(s) and used to have a rectangular arrow sign (same size as would be found on a two-way road or residential street!) at what isn't really that much of a curve.

[jeffandnicole]

As one crosses the Del Mem Br into NJ and stays on 295 North, they quickly encounter an unannounced series of curves that would surprise infrequent drivers as to their sharpness. They can be handled at 55 or 60 in cars when the driver is used to and expects the curves; trucks are generally going about 50 thru this stretch.

(Edited because I can't type on an eye phone.)

[Brandon]

*  WB I-80 in Nebraska between Omaha and Lincoln has a curve with chevrons before crossing the Platte River, but I'm not seeing any advance curve signs:  Streetview

I've been there, and it is easily handled at 75 mph (the speed limit in the area).

[getemngo]

If we can extend this to non-Interstate freeways... US-131 in downtown Grand Rapids. No, not the "S-Curve", as locals call it, which is very well signed with a variable speed limit sign usually displaying 50 or 45.

Rather, it's the curves where US 131 crosses over itself at the I-196 interchange, especially the last two-thirds heading southbound. (Northbound is manageable.) Things were fine when the speed limit was 55, but at 70, there's no warning whatsoever, no chevrons, and the curves are a lot sharper than they look. Street View doesn't do it justice.

[Brian556]

quote from roadman65:

In the OP I noticed he mentioned I-75 in Northern Florida.  I am guessing he is talking about a curve in Pasco County just north of FL 52.  I rode that curve many times, and it is not safe at 70 mph, especially with the cruise control engaged.

I wrote FDOT about it, but they said it was not a big issue to warrant warning signs, but I feel it is.

Thank you. Good to know that somebody else agrees with me on this.

[Avalanchez71]

I've noticed this occurs quite frequently.
Curves on all other types of highways, whether they pose a hazard or not, get curve signs. Most get chevrons. Yet, on Interstates, where expectations of a safe road are higher, there are curves need warning but have none.

Example#1. On I-40 EB in or near Jackson, TN; there is a curve so bad that the 18-wheeler and SUV in front of me nearly lost control because of it. This situation appears to be a design flaw, as there appears to be no need for a substandard curve at this location. The only warning is two low-mounted chevrons. Curve with advisory speed signs are really needed.

Example #2: I-75 in northern Florida. I encountered two curves that were sharp enough to not feel safe at the 70 MPH speed limit. Because of large vehicles in other lanes, you really can't see far enough ahead to see if traffic is stopping.

The previous two examples were In rural areas. Due to the frequent use of cruise control In rural areas, these are more hazardous. Without cruise control, you are likely to naturally slow down to the safe speed without realizing it.

In addition to curve signs, delineators are really on these curves.

Where was that on I-40?  I would like to cross-reference an accident count of the location.  I haven't been out that way lately but will need to go some time in August.

[TEG24601]

In all my travels, I actually find the chevrons to be rare in most cases.  I usually only see them if the road isn't properly banked, or banked for a speed lower than what is signed.  On Interstates, I primarily fine chevron signs in the mountains, especially down hill, or of the curve is greater than 45°.

[J N Winkler]

(Platte River curve, I-80 Nebraska)

I've been there, and it is easily handled at 75 mph (the speed limit in the area).

I have also been there, and handled it on cruise control at 75 MPH, but I would not consider it easy at all--there really is very little slack in the design.

This part of I-80 was built under NDOR contract number NH-80-9(823) (the I-80 West of Mahoney/Ruff Road contract), which was let July 21, 2005.  I have the construction plans filed; if there is interest, I'll dig them up and extract the data for this curve, and we can see exactly how bad it is.

Speaking more generally, I think we sold ourselves short as a country when we allowed curves of up to 3° on Interstates in flat terrain.  Other countries use stricter maxima:  in Britain it is 2°, and in Germany it is approximately 1°.  2° is approximately where accident risk due to geometric factors is at a minimum, so to allow curves of up to 3° builds more risk into our Interstates than is present in comparable facilities elsewhere.  This is further complicated by our traditionally very sloppy attitude toward design consistency:  for example, we allow different levels of superelevation for the same curve radius and the same design speed depending on the maximum superelevation adopted for a given segment of road.

[Avalanchez71]

How about I-65 just north of SR 254 (Old Hickory Blvd) coming into Metropolitan Nashville/Davidson County from Williamson County?  The road has a sudden small climb with a twist.  No warning is given and it almost feels like you are going to crash into a vehicle in the next lane over.

[CrystalWalrein]

I-70 through the Rockies. If it weren't for continuity it wouldn't deserve Interstate designation.

[cpzilliacus]

It could be that DOTs are reactive rather than proactive. It took a fiery explosion which claimed the life of a tanker truck's driver for Md. SHA to install this flashing curve warning sign.

I remember that one well.  I was watching an Orioles game at Camden Yards and the column of smoke was clearly visible from the resulting fire and explosion.