New Jersey Turnpike

[shadyjay]

Totally off-topic, but I just travelled the Turnpike today and saw they shut down the outer roadway (Cars/Trucks/Buses) northbound for emergency vehicles only. Wonder if that's been that way for a while since the pandemic started.

I was on the turnpike last week, from Exit 6/PA Turnpike up to the north end, and all lanes/roadways were open.  In fact, it was my first time since the 90s on the turnpike south of Exit 10.... what a difference!  Still gonna take a minute to get used to the MUTCD signage north of Exit 9.

Photos here:
https://www.flickr.com/photos/shadyjay/albums/72157713731030436

[jeffandnicole]

NJDOT, after a few cross-over median crashes that resulted in deaths, installed guardrails across nearly all medians where it's possible for a vehicle to cross over.  Usually they offset the guardrail to one side, which still allows one direction to have most of the median for a recovery zone, and the other side to have enough room for at least 12' of paved/unpaved shoulder.  Overall it seems to work out well.

A graded median 150 feet wide is possible for a vehicle to cross over.  Where do we draw the line?

A lot of this ultimately comes down to politics and public perception.  Traditional guidelines called for certain width medians designed a certain way to create a recovery zone. But standards always evolve and change over time.  While the recovery zone was created to minimize damage, the benefits of a guardrail to nearly eliminate the minor risk of a car crossing into the opposing direction is becoming a preferred standard in many jurisdictions, regardless of median width.  This in turn may change the standard of the median to compensate for the guardrail being present anyway.

There's probably also the 'innocent driver' risk, where someone driving one way gets hit by an errant driver going the other way.  However, compare it to a driver going down the road, leaving to the right, and hitting a tree.  It's assumed the driver that left the roadway only harmed themselves, not an innocent driver going the opposing direction.  It may not be completely true, especially if there's innocent victims in that car, but that's how public perception goes.

You know the standards and rules well no doubt, and you will design the roadway as the standards exist.  As long as you do your job, it's out of your hands - and your responsibility - if another engineer or supervisor modifies the plans to add guardrail where it's not totally necessary.

[jeffandnicole]

Totally off-topic, but I just travelled the Turnpike today and saw they shut down the outer roadway (Cars/Trucks/Buses) northbound for emergency vehicles only. Wonder if that's been that way for a while since the pandemic started.

Not that it made a huge difference - even at 9AM, it was pretty smooth sailing and light traffic.

As indicated by others, less traffic on the Turnpike allows them to do daytime closures vs. nighttime closures, but that's the only reason why the roadway is closed.  Earlier this week the inner roadway was closed one day in a similar fashion. 

But otherwise, I think people are thinking way too much into the closure of a roadway. I haven't seen this same thought process regarding express vs. local roadway setups, for example. 

What is the point of a 35 mph speed limit?

No clue; probably just a default. It's 65 the rest of the highway, and the emergency vehicles I have seen go by - in both directions on that one northbound roadway - are certainly not going 35.

Yeah, it's some sort of default, and the signs flash very slowly...like a slow, mocking clap.   As you saw, the work vehicles on the roadway are generally moving quite fast when they're not actively working.  For that matter, the work vehicles on the Turnpike move quite fast anyway.  It's a bit surprising to be driving 80 mph, and still get passed by an orange NJTA pickup truck! lol

[jeffandnicole]

https://www.njta.com/media/5179/proposed-2020-capital-improvement-program.pdf

Whomever shared that document, thank you!

Just a few random notes:

Page 19: GSP Interchange 17 Improvements

Construction of the missing movements between the Garden State Parkway and Sea Isle Blvd (CR 625) to complete as a full interchange by providing new movements from Parkway northbound to Sea Isle Blvd eastbound and Sea Isle Blvd westbound to GSP southbound eliminating the need to travel several miles to the south and use Interchange 13.

Heh...I liked how they tried to term it as eliminating the need to travel to Exit 13.  They know all too well everyone makes the U-turn just north of this interchange thru the travel plaza.  The old NJHA used to be a lot more permissive about this move in writing; the NJTA seems to shy away from talking about this movement. Although it's completely legal, they don't like the need to get from the right onramp to the left service plaza ramp NB, and vice-versa SB, in about a 1/2 mile span of travel.

Page 21: GSP - Eliminating Exit 30; Full interchange at Exit 29

Interesting Project to eliminate Exit 30 in favor of Exit 29.  I think a lot of people on Laurel Drive will appreciate that, and there's no businesses in that immediate vicinity that would be impacted. However, it's noted that CR 559 will probably need upgrading and the new double left turn lane coming off the Causeway onto 559 may become a bit overloaded during prime travel periods.

Page 28 - NJ Tpk - Extending the 4th Lane around Exit 13. 

I remember when they did the 4th lane widening for the HOV lane and decided the cost was too high in this area to add the 4th lane.  Never cared for that decision in the first place.

Page 29-30 - Conversion to AET

High price tag of $900 million, probably due to the need to remove every toll plaza, and there's an incredible number of utilities, tunnels and other hidden items to consider.  Of course, they're getting a practice run at it right now without toll collection, and may get some sort of idea what the payment response rate will be.

Various projects - Wozzers of price tags

The cost of widenings is just insane.  And I'm usually defending the price tags due to, well, it being NJ. But just incredible estimates. Who knows...maybe the new normal after Covid-19 will change traffic patterns significantly enough to reduce the need on some of those widenings.

[Beltway]

A graded median 150 feet wide is possible for a vehicle to cross over.  Where do we draw the line?

A lot of this ultimately comes down to politics and public perception.  Traditional guidelines called for certain width medians designed a certain way to create a recovery zone. But standards always evolve and change over time.  While the recovery zone was created to minimize damage, the benefits of a guardrail to nearly eliminate the minor risk of a car crossing into the opposing direction is becoming a preferred standard in many jurisdictions, regardless of median width.  This in turn may change the standard of the median to compensate for the guardrail being present anyway.

It is hard to envision an errant vehicle crossing a 60+ foot wide median unless it was deliberately driven into the opposing lanes, and then it wouldn't be 'errant.'  It would attempted autocide.

[sprjus4]

It is hard to envision an errant vehicle crossing a 60+ foot wide median unless it was deliberately driven into the opposing lanes, and then it wouldn't be 'errant.'  It would attempted autocide.

Hard to envision, but can happen. Why risk the potential of it happening, a head-on collision from happening, an innocent person being killed on impact, when a barrier would prevent it? VDOT recently installed cable barrier along I-664 which has a 64 foot median.

The US-17 Dominion Blvd example I posted only has a 46 foot median, and certainly warrants cable barrier, such that should've been installed back in 2016 when it was constructed.

As far as NCDOT's policy of installing cable guardrail on freeway medians up to 85 ft, it's certainly a good safety feature to have, and I fully support it. It may not be necessary in the 70s and up, but certainly 60 ft or less should have it. With the cable guardrail centered, with a standard median width of 46 ft, you have 23 ft of clear zone, and that number only increases the larger the median. That clear zone you mention is non-existent on freeways with jersey barrier or narrow medians with guardrail.

Why did it take VDOT so long to install cable barrier along I-64 where the median was only 20 ft with a 65 mph speed limit? I can't imagine the amount of head-on collisions that have occurred since that stretch was opened in the 1960s.

[Alps]

It is hard to envision an errant vehicle crossing a 60+ foot wide median unless it was deliberately driven into the opposing lanes, and then it wouldn't be 'errant.'  It would attempted autocide.

Hard to envision, but can happen. Why risk the potential of it happening, a head-on collision from happening, an innocent person being killed on impact, when a barrier would prevent it? VDOT recently installed cable barrier along I-664 which has a 64 foot median.

The US-17 Dominion Blvd example I posted only has a 46 foot median, and certainly warrants cable barrier, such that should've been installed back in 2016 when it was constructed.

As far as NCDOT's policy of installing cable guardrail on freeway medians up to 85 ft, it's certainly a good safety feature to have, and I fully support it. It may not be necessary in the 70s and up, but certainly 60 ft or less should have it. With the cable guardrail centered, with a standard median width of 46 ft, you have 23 ft of clear zone, and that number only increases the larger the median. That clear zone you mention is non-existent on freeways with jersey barrier or narrow medians with guardrail.

Why did it take VDOT so long to install cable barrier along I-64 where the median was only 20 ft with a 65 mph speed limit? I can't imagine the amount of head-on collisions that have occurred since that stretch was opened in the 1960s.

It's cost-benefit. Lives have costs. Guiderail has a cost. Do the math and decide.

[Beltway]

It is hard to envision an errant vehicle crossing a 60+ foot wide median unless it was deliberately driven into the opposing lanes, and then it wouldn't be 'errant.'  It would attempted autocide.

Hard to envision, but can happen. Why risk the potential of it happening, a head-on collision from happening, an innocent person being killed on impact, when a barrier would prevent it? VDOT recently installed cable barrier along I-664 which has a 64 foot median.

Again, the "if it saves one life" fallacy.

What if someone who would have recovered safely in 64 feet, now hits a guardrail that is 15 feet from the roadway, and the car turns over, and 3 people get killed?

It would be extraordinarily rare for an errant vehicle to cross 64 feet from the roadway.

It would not be uncommon for a vehicle to hit a fixed object 15 feet from the roadway.

It's cost-benefit. Lives have costs. Guiderail has a cost. Do the math and decide.

I would like to see engineering studies that would analyze that.  For a given median width, accident costs with and without a median barrier, and costs for the median barrier.

I have read lots of traffic engineering topical studies but have never seen this analyzed. 

[Alps]

It is hard to envision an errant vehicle crossing a 60+ foot wide median unless it was deliberately driven into the opposing lanes, and then it wouldn't be 'errant.'  It would attempted autocide.

Hard to envision, but can happen. Why risk the potential of it happening, a head-on collision from happening, an innocent person being killed on impact, when a barrier would prevent it? VDOT recently installed cable barrier along I-664 which has a 64 foot median.

Again, the "if it saves one life" fallacy.

What if someone who would have recovered safely in 64 feet, now hits a guardrail that is 15 feet from the roadway, and the car turns over, and 3 people get killed?

It would be extraordinarily rare for an errant vehicle to cross 64 feet from the roadway.

It would not be uncommon for a vehicle to hit a fixed object 15 feet from the roadway.

It's cost-benefit. Lives have costs. Guiderail has a cost. Do the math and decide.

I would like to see engineering studies that would analyze that.  For a given median width, accident costs with and without a median barrier, and costs for the median barrier.

I have read lots of traffic engineering topical studies but have never seen this analyzed. 

I think that's where the decision comes from to make a 60' median the standard (or possibly less in some states). P(crossover) x $(fatality) compared to $(guiderail+maintenance) per year.

[sprjus4]

SAFETY BENEFITS OF MEDIAN
BARRIER AND ROADSIDE GUARDRAIL

Excerpts:

Their efficacy in mitigating crash severity is assessed by a crash modification factor (CMF), an estimate of the change in crashes expected after implementing a given countermeasure at a specific site. A CMF reflects the safety effect of a countermeasure, whether it is a decrease in crashes (CMF less than 1.0), increase in crashes (CMF more than 1.0), or no change in crashes (CMF of 1.0) (1). For example, in Table 1, CMF of median barrier for preventing cross-median fatal injury crashes is 0.34. This means, the expected number of fatal crashes after installation of median barrier will be reduced by approximately 66 percent.

Flexible barriers consist of low-tension and high- tension cable barrier (HTCB) systems. HTCBs have replaced the low-tension cable barriers in most states due to improved performance and maintenance benefits. Cable barriers are best suited for deployment at locations with wide median areas and allow drivers to make a safe stop without re-entering the traffic or entering the travel lane of oncoming traffic (i.e., wrong-way driving). Their larger deflections allow for softer impacts, resulting in fewer injuries, and the open design allows for wind, sand, and snow to pass through the system.

One major consideration about median barriers is the width of the median and knowing where and what type of barrier should be installed. The common median width for installing cable barriers is 40 feet to 75 feet. A few other factors to consider include the median slope, the amount of traffic, the crash history, and the cost. HTCBs are in wide use across the country and are seen as more effective than low-tension cable barriers. Figure 3 shows an installation of HTCB as a median barrier. HTCB can be placed on slopes as steep as 4:1 or flatter. It should be noticed that the HTCB can also be used as a roadside barrier.

Testing criteria specific to cable barriers was introduced for the first time in the MASH 2009 edition. These criteria include minimum fence lengths, minimum tension for testing, and placement of hardware in the vehicle impact zone. In MASH 2016, six new tests (Tests 13 through 18) are added to test the effectiveness of cable barriers at 6:1 and 4:1 slopes for different performance conditions, including:
- Ability of a cable barrier to contain and redirect light trucks and SUVs as well as prevent barrier override.
- Ability of a cable barrier to safely contain and redirect small passenger vehicles without resulting in excessive vehicular instabilities and/or rollover.
- Ability of a cable barrier to safely contain and redirect small passenger vehicles as well as prevent barrier underride, component penetration into the occupant compartment, and excessive deformations of the A-pillar, roof, or windshield.
- Ability of a cable barrier to safely contain and redirect small passenger vehicles after traveling across the center of a ditch and up the back slope.
- Ability of a cable barrier to contain and redirect mid-size passenger sedans by preventing vehicle penetration through vertically adjacent cables.
- Ability of a cable barrier to safely contain and redirect light trucks and SUVs after traveling across the center of a ditch and up the back slope.

The end of the report features success stories from the installation of cable guardrail. The first two examples, a semi-truck and a passenger vehicle, both with median widths visibly over 40 foot wide, prevented head-on collisions that otherwise would've occurred and likely killed innocent drivers, notably the truck.

https://youtu.be/kiWSE4r_uS0

1:24 is a perfect example of what happens when you lack median barrier, and that example appears at least 50 foot wide.

The Missouri Department of Transportation did a video back in 2011 that actually discussed the issue with a reduced clear zone, indicating the severity of those crashes are far less and certainly a price to pay in order to prevent median crossover crashes.

https://youtu.be/IZTtBN7CHxY

The Arizona Department of Transportation claiming median crossover crashes on a section of I-10 with an 80 foot median are very rare and installing a cable barrier would only do more harm; however actual numbers of crashes, injuries, and fatalities go against that fallacy claim as there's been numerous of them head on, even with the large median. The cost of median barrier installation would be significantly less than the costs of lawsuits, claims, etc. the lack of barrier and deadly crashes have costed. At 80 foot wide, a centered cable guardrail would provide about 40 foot of clear zone on either side, at that point any potential collisions likely to be non-fatal and property damage. This, as opposed to a car flying across 80+ mph with no separation, assuming 80 feet will stop them, and like the numerous times mentioned in the video if not, right oncoming traffic into a fatal collision. I'm not necessarily saying all medians 80 feet wide need cable guardrail, but on sections like this where clusters exist based on previous records despite ADOT calling fallacy, they should certainly be considered and not pushed off by the state merely because of poor data on their end.

https://youtu.be/vxhcubOLyPY

Additional studies have been completed by NCDOT, TxDOT, WsDOT, and others that can be easily accessible online.

[J Route Z]

So a man named Jeff Tittel, director of the New Jersey Sierra Club, wrote in the NJ.com opinion section to voice his concerns with the future widening projects of the Turnpike and Parkway. It explains that these types of projects will be affecting environmentally sensitive areas. While the concerns are understandable, IMO it's much needed based on the increasing volume of traffic, especially to alleviate bottlenecks on the southern portion of the Turnpike in the vicinity of exit 4 down to the southern terminus where it narrows down from 3 to 2 lanes.

https://www.nj.com/opinion/2020/04/turnpike-authority-capital-plan-is-irresponsible-opinion.html

[Beltway]

SAFETY BENEFITS OF MEDIAN
BARRIER AND ROADSIDE GUARDRAIL

. The common median width for installing cable barriers is 40 feet to 75 feet. A few other factors to consider include the median slope, the amount of traffic, the crash history, and the cost. HTCBs are in wide use across the country and are seen as more effective than low-tension cable barriers. Figure 3 shows an installation of HTCB as a median barrier. HTCB can be placed on slopes as steep as 4:1 or flatter. It should be noticed that the HTCB can also be used as a roadside barrier.

Did you notice that the author, American Traffic Safety Services Association, is a private company and an advocacy group -- 
American Traffic Safety Services Association represents the road, traffic, and highway safety industry with effective legislative advocacy, traffic control safety training, and a far-reaching member partnership.
HTCB is a recent guardrail design, High Tension Cable Guardrail.  I see that they have their advocates out marketing their product.  Interesting informercials that you posted there!

The NCDOT study is "Median Barrier Placement on Six-lane, 46-foot Median Divided Freeways."  Those 6-lane freeways are by nature high volume freeways and that width and volume looks in the zone of possible logical warrants.  The cost of the guardrail per vehicle mile traveled goes down as the volume goes up.   Up to 75 feet sounds like something promoted by certain elements of the highway contracting industry.

[jeffandnicole]

Anti-barriers

Why are you so against guardrails, cable barriers and other protective measures?  Why do you counter with the remote possibility of "a car could topple over and kill 3 family members", while minimizing a vehicle getting thru a median and killing a family in a head-on crash? 

As detailed by some here, and by preference in many states, it's becoming more preferred to have some sort of barrier where the benefits generally are going to outweigh the negatives.  Site as many engineering stats as you want - barriers are preferred.

[Beltway]

Anti-barriers  [jeffandnicole edited my comments]

Why are you so against guardrails, cable barriers and other protective measures?

This is a stupid comment.  I always have been in favor of  guardrails, cable barriers and other protective measures.

Why do you counter with the remote possibility of "a car could topple over and kill 3 family members", while minimizing a vehicle getting thru a median and killing a family in a head-on crash? 

The "if it saves one life" fallacy.  Need to determine the probabilities of each, and the cost and benefits associated.

As detailed by some here, and by preference in many states, it's becoming more preferred to have some sort of barrier where the benefits generally are going to outweigh the negatives.  Site as many engineering stats as you want - barriers are preferred.

No question about a 10-foot median on the PA Turnpike needing a median barrier.

The 25-foot median on the NJTP (this is an NJTP thread) with such high volume, again, no question about needing a median barrier.  Median barrier is required.

For the universe of roads out there, we need a better justification argument than "it makes me feel good," before attacking transportation agencies for not installing High Tension Cable Barrier (HTCB) in questionable locations.

[jeffandnicole]

It should be noted that when the PA Turnpike originally opened, I don't believe they did have a median barrier.  Just 1 of many examples of how engineering standards evolves over time.

When the NJ Turnpike opened, as we discussed, it was a standard metal W guardrail barrier, not a concrete jersey barrier. Just 1 additional example of how engineering standards evolve over time.

Why do you counter with the remote possibility of "a car could topple over and kill 3 family members", while minimizing a vehicle getting thru a median and killing a family in a head-on crash? 

The "if it saves one life" fallacy.  Need to determine the probabilities of each, and the cost and benefits associated.

Isn't that exactly what Alps has said, and you argued with him? Twice?

As detailed by some here, and by preference in many states, it's becoming more preferred to have some sort of barrier where the benefits generally are going to outweigh the negatives.  Site as many engineering stats as you want - barriers are preferred.

No question about a 10-foot median on the PA Turnpike needing a median barrier.

The 25-foot median on the NJTP (this is an NJTP thread) with such high volume, again, no question about needing a median barrier.  Median barrier is required.

For the universe of roads out there, we need a better justification argument than "it makes me feel good," before attacking transportation agencies for not installing High Tension Cable Barrier (HTCB) in questionable locations.

However, that's often the justification used for reducing speed limits when engineering studies don't require it, stop signs, traffic lights, roundabouts and other traffic control devices where less restrictive controls would satisfy traffic demands, bicycle lanes when there's projected to be little to no usage of them, etc.

Not saying it's right, but "it makes me feel good" is often the overriding reason for a fair amount of "stuff" in questionable locations.

[Beltway]

For the universe of roads out there, we need a better justification argument than "it makes me feel good," before attacking transportation agencies for not installing High Tension Cable Barrier (HTCB) in questionable locations.

However, that's often the justification used for reducing speed limits when engineering studies don't require it, stop signs, traffic lights, roundabouts and other traffic control devices where less restrictive controls would satisfy traffic demands, bicycle lanes when there's projected to be little to no usage of them, etc.
Not saying it's right, but "it makes me feel good" is often the overriding reason for a fair amount of "stuff" in questionable locations.

Well, that is a lack of engineering that I find objectional when and if that occurs on the highway system, given limited budgets.

The average cost I seem to find online for HTCB is about $250,000 per mile, and for the usual installation of two runs, that is $500,000 per mile; and that would be $5 million for 10 miles.  Then there are maintenance costs afterward.

So there is a need for clear engineering justification for a particular location before such an expenditure is authorized.

[sprjus4]

.  Need to determine the probabilities of each, and the cost and benefits associated.

Except - and was quite predicted when posting - such studies regarding these would not be "good enough"  as you don't agree with the viewpoints.

You ask for reports - and when you don't agree with them - they are invalid.

For the universe of roads out there, we need a better justification argument than "it makes me feel good," before attacking transportation agencies for not installing High Tension Cable Barrier (HTCB) in questionable locations.

Except the specific Arizona example was a high frequency crash location with an umpteenth amount of median crossover collisions in the past decade, and the transportation agency, using their own data which was not nearly as extensive as the records presented in court, and used that as a basis to claim it would only hurt people further.

If a car flies across a 50 or 60, even 70 foot median, is it supposed to come a complete stop at 75 - 80 mph? You've claimed this, but evidence shows otherwise. At this point, the installation of cable guardrail has proved successful countless times to mitigate those crossovers, and limit any damage to a non-fatal encounter with the cable as opposed to another car head on at that same 75 - 80 mph speed, killing both in the process.

Cable guardrail has been proven successful, and is evident by its use in numerous states across the country, notably those with medians wider than 40 feet which supposedly don't need them.

[jeffandnicole]

The average cost I seem to find online for HTCB is about $250,000 per mile, and for the usual installation of two runs, that is $500,000 per mile; and that would be $5 million for 10 miles.  Then there are maintenance costs afterward.

So there is a need for clear engineering justification for a particular location before such an expenditure is authorized.

Engineering justification is easy to receive in this case. As shown throughout the past few dozen posts, the money spent is worth the safety benefits implied to the motorists and elected or appointed officials.

[sprjus4]

The average cost I seem to find online for HTCB is about $250,000 per mile, and for the usual installation of two runs, that is $500,000 per mile; and that would be $5 million for 10 miles.  Then there are maintenance costs afterward.

Usually when cable guardrail is installed, it's usually one line in the center median or positioned on one side of the roadway, not two.

The City of Chesapeake's recent project for 3.5 miles cost $767,680, so around $219,337 per mile. For 10 miles, that's $2,193,370. That's a minor cost, and for the safety benefits it provides, including lives saved which apparently is fallacy and a head-on collision is preferred to save money, is well worth the investment to the states that do such programs. If it's incorported into a new freeway, it's nothing compared to the cost of the highway itself. How about the amount in lawsuits, claims, that Arizona for example had to deal with, much higher than the cost of installing cable guardrail.

[sprjus4]

The average cost I seem to find online for HTCB is about $250,000 per mile, and for the usual installation of two runs, that is $500,000 per mile; and that would be $5 million for 10 miles.  Then there are maintenance costs afterward.

So there is a need for clear engineering justification for a particular location before such an expenditure is authorized.

Engineering justification is easy to receive in this case. As shown throughout the past few dozen posts, the money spent is worth the safety benefits implied to the motorists and elected or appointed officials.

And through various studies and reports, though are fallacy because they don't oppose guardrails.

[jeffandnicole]

The average cost I seem to find online for HTCB is about $250,000 per mile, and for the usual installation of two runs, that is $500,000 per mile; and that would be $5 million for 10 miles.  Then there are maintenance costs afterward.

So there is a need for clear engineering justification for a particular location before such an expenditure is authorized.

Engineering justification is easy to receive in this case. As shown throughout the past few dozen posts, the money spent is worth the safety benefits implied to the motorists and elected or appointed officials.

And through various studies and reports, though are fallacy because they don't oppose guardrails.

When NJ decided for guardrails in nearly all medians, they decided against cable due to the high maintenance costs and loss of safety benefits between the time being hit and getting replaced. Standard guardrail is much more expensive, but NJDOT determined it's worth the overall benefits.

To roll this back to that turnpike in NJ, when they engineered the Jersey barrier they use, it was designed for a 55 mph truck to hit it at a 15 degree angle - much stronger than traditional jersey barriers. It was designed during the NMSL days. Even though the limit on the Turnpike has been 65 for a few decades now and true travel speeds above that, the NJTA must figure that it's still adequate. It should be noted that they still use standard guardrail in the dual-dual section between parallel roadways slowing in the same direction, but I guess they figure that even if a truck gets thru that, it will generally be a sideswipe accident which tends to be less severe.

[Beltway]

Moderators, feel free to move this sub-discussion somewhere else if you want -- I have no objections to having a median barrier on the NJTP with its 25-foot medians and outer separators.  Those are narrow medians and the highway has very high total volumes and very high truck volumes.

.  Need to determine the probabilities of each, and the cost and benefits associated.

Except - and was quite predicted when posting - such studies regarding these would not be "good enough"  as you don't agree with the viewpoints.
You ask for reports - and when you don't agree with them - they are invalid.

I dismissed the one that you posted from an industry advocacy group.

Where is the summary data from an officially commissioned engineering report?

The average cost I seem to find online for HTCB is about $250,000 per mile, and for the usual installation of two runs, that is $500,000 per mile; and that would be $5 million for 10 miles.  Then there are maintenance costs afterward.

Usually when cable guardrail is installed, it's usually one line in the center median or positioned on one side of the roadway, not two.
The City of Chesapeake's recent project for 3.5 miles cost $767,680, so around $219,337 per mile. For 10 miles, that's $2,193,370. That's a minor cost, and for the safety benefits it provides, including lives saved which apparently is fallacy and a head-on collision is preferred to save money, is well worth the investment to the states that do such programs.

On a 36-foot median of a highway that carries in excess of 30,000 AADT that seems logical enough.  Another problem with a median that size is that the slopes need to be steep enough to establish drainage to the ditch in the center of the median, that it could flip a car over, so a guardrail can prevent that from happening, and that is not a cross-median incident but still a problem with a narrow grass median.

On a 70-foot median and 15,000 AADT, for example, show me the data, not emotional arguments.

If it's incorported into a new freeway, it's nothing compared to the cost of the highway itself. How about the amount in lawsuits, claims, that Arizona for example had to deal with, much higher than the cost of installing cable guardrail.

It would depend on the size of the lawsuits, how much they cost to defend, and how much (if any) the cost of the judgements.

Government agencies nearly always claim sovereign immunity, which means that they cannot be sued in court by private entities.

If a car flies across a 50 or 60, even 70 foot median, is it supposed to come a complete stop at 75 - 80 mph?

Try calculating how far that vehicle will travel in the 70 foot median if it enters at a 10 degree angle and the driver makes an effort to mitigate that.  I will work up some calculations, but that would probably be 600 feet or more.

[sprjus4]

Where is the summary data from an officially commissioned engineering report?

On a 70-foot median and 15,000 AADT, for example, show me the data, not emotional arguments.

It's not even worth trying to provide any data to you - you have a consistent habit of dismissing anything you may not agree with. For instance, you requested studies on cable guardrails, when provided, you dismissed them as being "advocacy" because you disagree with the viewpoint. Consider if you agreed with the conclusion of the study - you would have no problem utilizing it. This is happened umpteenth times across this forum on many different subject areas.

Many states have properly installed cable guardrail in larger medians, up to 70 feet wide, have reaped the safety benefits of them, including examples, some in the report I provided, of how they have actually saved lives - on larger medians - and will continue to do so. North Carolina, Texas, Mississippi, South Carolina, and Alabama are just a few. Some have been installed in Virginia in recent years and may well expand to other locations.

[Beltway]

On a 70-foot median and 15,000 AADT, for example, show me the data, not emotional arguments.

It's not even worth trying to provide any data to you - you have a consistent habit of dismissing anything you may not agree with. For instance, you requested studies on cable guardrails, when provided, you dismissed them as being "advocacy" because you disagree with the viewpoint. Consider if you agreed with the conclusion of the study - you would have no problem utilizing it.

You don't have an argument, other than emotional.

A few states install guardrail in medians that wide, and you attack the others that don't -- that puts the burden of proof on you.

of how they have actually saved lives

How many lives have been saved?

[sprjus4]

Try calculating how far that vehicle will travel in the 70 foot median if it enters at a 10 degree angle and the driver makes an effort to mitigate that.  I will work up some calculations, but that would probably be 600 feet or more.

Assuming it enters at that angle. What if a vehicle quickly swerves to the left to avoid an object, and loses control coming in at a 45 degree or more angle? How about on a curve? Lots of possibilities.

You don't have an argument, other than emotional.

A few states install guardrail in medians that wide, and you attack the others that don't -- that puts the burden of proof on you.

Please. I've provided plenty of proof, and you dismiss it because it's "advocacy".

I suppose the countless amount of times median guardrail has saved lives and prevented head-on collisions is only "emotional" and has no place being implemented.

How many lives have been saved?

I could through, research the topic further outside of the reports I've already provided that have proven this, but I'm not even going to waste the time considering you'll just call it "advocacy", whether it was conducted by a DOT, private agency, or whomever.

If you're curious, do the research yourself. Plenty is out there on the internet.