Cable guard rails

[roadman65]

When I lived in New Jersey growing up as a kid I remember New Jersey's highways had cables attached to white posts instead of today's W guard rails.  They were all replaced slowly all throughout the 1980's so that by 1990 they were all gone, but were mostly all there in the 1970's.  It was pretty much concrete highways with those white post guide rails all growing up for me.  I think it was when NJDOT paved over the original concrete pavements when they included guardrail replacement.

I also remember Pennsylvania having them as well and parts of New York State in addition to their box rails but not white painted like NJ had but bare medal.  The western part of the PA Turnpike used them west of Breezewood and the rest of PA highways including US 22.  Now they were not like NJDOT and the rest of the Garden State removing them all over time, but they did replace many of them though.  New York still has them as I saw back in 12, but in remote places along their interstates.

Florida now has them on the FL 528 in the median of the freeway from FL 417 to FL  520 as the deterrence to prevent median crossovers as other Florida Freeways use the W guard rail to stop wayward vehicle crossovers.  The FL 528 cables are attached to skinny mono tube posts unpainted similar to PA's.

What areas still use these cable stayed stoppers to this day other then Florida's Beachline and why were they replaced in New Jersey and parts of PA?  I know that my dad told me the nature of those cables as they were flexible which slowed down any object that breached them over the fixed medal rails which are not which I can understand, but why the switch to fixed medal and enough for NJDOT to rid themselves of all of their cable stayed devices?

[freebrickproductions]

We have them in the median of the interstates in Alabama.

[Big John]

Many states have put them in the median now as a lower-cost alternative to try to prevent a wayward vehicle from entering oncoming traffic.  Applies to wide depressed medians only. Placement is usually on one side of traffic rather than in the ditch.

[WillWeaverRVA]

Virginia has these in places, particularly along the stretch of I-95 between Fredericksburg and Ashland, although recently VDOT has been replacing them with regular guardrails as traffic increases.

[jeffandnicole]

PA still has them on I-95 between Delaware & Chester.  (I think maybe near the airport as well)

I remember reading NJ was going to add cable barriers to medians that didn't have any protection. While their cost is cheaper than metal guiderail, once they're hit they aren't very effective until they're fixed, whereas a damaged guiderail may not look pretty but still retains most of its effectiveness.  After some experiences with a few installed cable barriers, NJ decided to use metal guiderail instead.  Depending on the road, they've used W or Thrie.

[slorydn1]

We have the cable barriers on both the US-70 freeway between Dover and the Freedom Memorial Bridge in New Bern, as well as on the new US-17 freeway alignment west of New Bern. The barrier on 70 has only been there for about 10 years or so, before that there was nothing but the wide median and luck.

[kphoger]

Many states have put them in the median now as a lower-cost alternative to try to prevent a wayward vehicle from entering oncoming traffic.  Applies to wide depressed medians only. Placement is usually on one side of traffic rather than in the ditch.

This doesn't apply to wide, depressed medians only. Take a look at GSV for I-44 several miles south of Walters, Okla., for an extreme example.

[hbelkins]

I remember the old cables with white posts, or white posts only, in Kentucky. Very, very, very few examples are left.

Kentucky is installing cable barriers in the medians of interstates and freeways on an increasing basis.

[briantroutman]

You can learn all about the compromises between various barrier types (strong vs. weak-post, rigid vs. flexible) by watching this FHWA video. If you want to jump right to the particulars of cable barriers, skip ahead to the 35-minute mark.

According to that video, there are relatively few places where cable barriers are appropriate. Unlike the typical W-beam guardrail setup, cable barriers are very flexible. By design, they deflect as much as 17 feet when hit, so they should only be used in places where there's a clear recovery area that extends more than 17 feet beyond the barrier. And since cable barriers are basically sacrificial (even one light hit, and the entire system needs to be replaced) they're ideally placed at least 20 feet from the edge of roadway.

In the past in Pennsylvania, I've seen cable barriers used on rural secondary state routes with narrow gravel shoulders and ditches, trees or other obstructions immediately behind (like this)–nearly the antithesis of FHWA's recommended scenario.

Cable barriers are the best for driver and car because the gradual deflection helps to absorb impact energy, reducing damage on both the vehicle and its occupants, but if a wide clear zone can't be created behind the barrier, or if the DOT can't maintain a cable barrier that's frequently hit, that would nullify the benefits.

[jeffandnicole]

You can learn all about the compromises between various barrier types (strong vs. weak-post, rigid vs. flexible) by watching this FHWA video. If you want to jump right to the particulars of cable barriers, skip ahead to the 35-minute mark.

According to that video, there are relatively few places where cable barriers are appropriate. Unlike the typical W-beam guardrail setup, cable barriers are very flexible. By design, they deflect as much as 17 feet when hit, so they should only be used in places where there's a clear recovery area that extends more than 17 feet beyond the barrier. And since cable barriers are basically sacrificial (even one light hit, and the entire system needs to be replaced) they're ideally placed at least 20 feet from the edge of roadway.

In the past in Pennsylvania, I've seen cable barriers used on rural secondary state routes with narrow gravel shoulders and ditches, trees or other obstructions immediately behind (like this)–nearly the antithesis of FHWA's recommended scenario.

Cable barriers are the best for driver and car because the gradual deflection helps to absorb impact energy, reducing damage on both the vehicle and its occupants, but if a wide clear zone can't be created behind the barrier, or if the DOT can't maintain a cable barrier that's frequently hit, that would nullify the benefits.

So you mean cable barrier set just off the pavement along I-95 in PA like this: http://goo.gl/maps/gzaAB isn't acceptable?  17 feet would put a car coming from 95 North into the center lane of 95 South!

[Caboosey]

I have been trying to get Caltrans (California DOT) to install one on Southbound Hwy 101 between Exit 191B and 191A in Pismo Beach, CA. The City of Pismo Beach want it, but Caltrans wont go for it. People can easily go off the road and hit cars on Price street / Hwy 1 head on. Someone already went off the road, Hwy 101 southbound, there once and killed two pedestrians on Price Street / Hwy 1 walking on sidewalk.

Location: https://www.google.com/maps/@35.1485899,-120.6492576,670m/data=!3m1!1e3
Streetview: https://www.google.com/maps/@35.148824,-120.649219,3a,75y,124.94h,79.93t/data=!3m4!1e1!3m2!1ssSpSPn8vXVWAjpYDMA70qg!2e0

News article: http://www.sanluisobispo.com/2010/10/16/1330911_pismo-fatality-freeway-pedestrian.html?rh=1

Caltrans 2010 design standards for Cable guard rails: http://www.dot.ca.gov/hq/esc/oe/project_plans/highway_plans/stdplans_US-customary-units_10/viewable_pdf/b11-47.pdf

[cl94]

New York still uses them, although they're mainly found on freeways. Typically placed in depressed medians or next to a gradual slope.

High-tension systems (what NY currently uses, for example) have a deflection of ~4 feet when hit by a passenger car and will remain effective outside of the crash area, even if hit. Exerts less force on vehicles than typical barriers.

[Brian556]

US 77 in Oklahoma still has some that are very old:

https://maps.google.com/maps?ll=34.429505,-97.143864&spn=0.000018,0.012392&t=h&z=17&layer=c&cbll=34.429505,-97.143864&panoid=3YoxuOY-PZfmPueGIy40yg&cbp=12,191.5,,0,0

[roadman]

I have been trying to get Caltrans (California DOT) to install one on Southbound Hwy 101 between Exit 191B and 191A in Pismo Beach, CA. The City of Pismo Beach want it, but Caltrans wont go for it. People can easily go off the road and hit cars on Price street / Hwy 1 head on. Someone already went off the road, Hwy 101 southbound, there once and killed two pedestrians on Price Street / Hwy 1 walking on sidewalk.

Location: https://www.google.com/maps/@35.1485899,-120.6492576,670m/data=!3m1!1e3
Streetview: https://www.google.com/maps/@35.148824,-120.649219,3a,75y,124.94h,79.93t/data=!3m4!1e1!3m2!1ssSpSPn8vXVWAjpYDMA70qg!2e0

News article: http://www.sanluisobispo.com/2010/10/16/1330911_pismo-fatality-freeway-pedestrian.html?rh=1

Caltrans 2010 design standards for Cable guard rails: http://www.dot.ca.gov/hq/esc/oe/project_plans/highway_plans/stdplans_US-customary-units_10/viewable_pdf/b11-47.pdf

Looking at the location, IMO you'd probably be better off lobbying for a standard guardrail instead a cable barrier due to the minimal lateral clearance between the 101 freeway and Prince Street.  This is because cable barriers are designed to deflect when hit, which could result in an errant vehicle still hitting pedestrians or vehicles on Prince Street.  Back to back standard W-Beam guardrails could be installed with the chain-link fence in between them.

[adventurernumber1]

I've seen plenty of cable guard rails around here on interstates. Here's one on Interstate 75 in GA, even getting into Metro Atlanta: https://www.google.com/maps/@34.080103,-84.639649,3a,75y,76.67h,85.6t/data=!3m4!1e1!3m2!1sA8QRU6ugQ8jA7CwCAjvRZA!2e0

There's also a good bit on non-interstate freeways like sections of:
- US 19/GA 400: https://www.google.com/maps/@34.240723,-84.097548,3a,75y,197.57h,84.37t/data=!3m4!1e1!3m2!1sUr9rHP93xOyMNA_qM77a9w!2e0
- US 78/Stone Mountain Freeway: https://www.google.com/maps/@33.830556,-84.181543,3a,75y,94.05h,80.69t/data=!3m4!1e1!3m2!1sfwSNmrHm-rjBvR9w6wUcxw!2e0

I find them to be pretty cool, and a good alternative for generic guard rails.

[slorydn1]

We have the cable barriers on both the US-70 freeway between Dover and the Freedom Memorial Bridge in New Bern, as well as on the new US-17 freeway alignment west of New Bern. The barrier on 70 has only been there for about 10 years or so, before that there was nothing but the wide median and luck.

Looking at other posts I should have included an example with mine:


https://www.google.com/maps/@35.099906,-77.055154,3a,75y,98.78h,90.12t/data=!3m4!1e1!3m2!1sFZ7S1TIWZcu66_bMy5kPog!2e0?hl=en


This is on US-17 North/US-70 East/NC-55 East at the approach to the Freedom Memorial Bridge (you can see where the cable ends and the normal guardrail begins up ahead). I like the DMS sign in the middle because the controls for it and the cameras sit on my desk at work. 

[Caboosey]

I have been trying to get Caltrans (California DOT) to install one on Southbound Hwy 101 between Exit 191B and 191A in Pismo Beach, CA. The City of Pismo Beach want it, but Caltrans wont go for it. People can easily go off the road and hit cars on Price street / Hwy 1 head on. Someone already went off the road, Hwy 101 southbound, there once and killed two pedestrians on Price Street / Hwy 1 walking on sidewalk.

Location: https://www.google.com/maps/@35.1485899,-120.6492576,670m/data=!3m1!1e3
Streetview: https://www.google.com/maps/@35.148824,-120.649219,3a,75y,124.94h,79.93t/data=!3m4!1e1!3m2!1ssSpSPn8vXVWAjpYDMA70qg!2e0

News article: http://www.sanluisobispo.com/2010/10/16/1330911_pismo-fatality-freeway-pedestrian.html?rh=1

Caltrans 2010 design standards for Cable guard rails: http://www.dot.ca.gov/hq/esc/oe/project_plans/highway_plans/stdplans_US-customary-units_10/viewable_pdf/b11-47.pdf

Looking at the location, IMO you'd probably be better off lobbying for a standard guardrail instead a cable barrier due to the minimal lateral clearance between the 101 freeway and Prince Street.  This is because cable barriers are designed to deflect when hit, which could result in an errant vehicle still hitting pedestrians or vehicles on Prince Street.  Back to back standard W-Beam guardrails could be installed with the chain-link fence in between them.

Caltrans kept complaining about the costs when i tried to push for regular guard rails, so I pushed for cable rails. I see about 4 cars per year going off of Hwy 101 and cross over into Price Street. I haven't seen any cars go off Price Street into Hwy 101 since there is a slight hill, lower speeds (speed limit is 35mph), and a fence.

Its about 15 feet from white line of Hwy 101 to the edge of road on Price Street.

[hbelkins]

New York uses this on NY 17:

[cbeach40]

MTO uses three cable guiderail as a roadside barrier on lower volume highways, in areas with a minimum of 3 m clearance from a hazard (due to the deflection of that barrier system). It is not used in median applications or adjacent to curb and gutter. Six cable guiderail with steel posts is technically permitted for median use, but cable systems in medians have fallen out of favour within the Ministry due to poor experience with them years back.

Cost wise, the installation and maintenance is actually cheaper than the "w-rail" barriers, with w-rail costing about 2.5 x as much to install, and 1.4 x as much to maintain (realistically, if a vehicle hits the barrier hard enough to knock out posts on a cable system it'll do some serious damage to the steel beam one too). The w-rail has a deflection of only 0.3-0.9 m, so it certainly is better at protecting from a hazard.

[cpzilliacus]

These used to be pretty common in Maryland years ago, but nearly all of them have been replaced by "W" beam barriers or Jersey wall-type concrete walls.

[hm insulators]

I think the stretch of Loop 101 in the western Phoenix metro area (by the football stadium) used to have cable guard rails down the center of the freeway but they'd been replaced by something more sturdy.

Anybody remember ordinary chain-link fence used to separate directions of travel? Growing up in southern California, the freeways all had ordinary chain-link fence down their centers. This was the 1960s and '70s.

[kphoger]

Many states have put them in the median now as a lower-cost alternative to try to prevent a wayward vehicle from entering oncoming traffic.  Applies to wide depressed medians only. Placement is usually on one side of traffic rather than in the ditch.

This doesn't apply to wide, depressed medians only. Take a look at GSV for I-44 several miles south of Walters, Okla., for an extreme example.

Now that I'm at a desktop computer, I'll link to an example.
Cable barrier used between roadways of I-44 in Oklahoma.  Narrow, paved median space.
http://goo.gl/maps/mWzJg

[Big John]

^^ Whoa.  I would not trust that to prevent an errant vehicle from crashing into that and avoid entering the oncoming lanes.

[adventurernumber1]

^^ Whoa.  I would not trust that to prevent an errant vehicle from crashing into that and avoid entering the oncoming lanes.

I agree. A concrete barrier of appropriate height is much needed in that situation. I don't think I've ever seen a cable guard rail used in such a way.

[Jardine]

There might be more, but the I-29 overpass over the UPRR 1 mile north of Modale, IA has the cable barrier leading up to a W barrier leading up to the overpass railing.