Movable median barrier coming to Golden Gate Bridge

[ZLoth]

From SF Gate:

Movable median barrier coming to Golden Gate Bridge

A movable median barrier, designed to prevent head-on collisions, is finally coming to the Golden Gate Bridge in January, but it will take a weekend-long closure to get it installed.

The bridge district's Board of Directors awarded contracts Friday to install the $30 million steel-and-concrete barrier, which will replace the yellow plastic tubes that now separate cars traveling in opposite directions - often only inches apart - across the landmark span.

The barrier - 12 inches wide, 32 inches tall and 11,538 feet long - will be placed on the bridge during a weekend closure tentatively scheduled to start just after midnight on Jan. 10, 2015, and end at 4 a.m. on January 12. The district had originally planned to install the barrier over a weekend in late October but decided the January date was likely to have less of an effect on traffic.

FULL ARTICLE HERE

[kendancy66]

The last time I drove across the bridge, a maintenance worker team in a truck was relocating the plastic barriers from one lane to another.   It is interesting how they are able to move those.  It will be a lot safer with the new barrier.  I wonder if the new barrier setup will be like the barrier on the Coronado bridge in San Diego (CA-75)

[TheStranger]

Noticing some of the comments on that page, I wonder...

- do people realize how much more usable the left lanes will be with a solid barrier (as opposed to one that is essentially traffic cones)?  Basically a capacity increase without having to widen anything.

- I don't expect the speed limits to be raised BUT in theory, now that crossovers would be near-impossible, who knows.

- With some of the toll booths being removed to facilitate the new barrier...as the Golden Gate Bridge is all-electronic tolling now, I wonder if they'll be able to create a wider left lane for those with Fastrak, just like on the Benicia Bridge.

[jeffandnicole]

A median barrier has been talked about for decades, said Denis Mulligan, the bridge district's general manager, but a barrier thin and light enough didn't previously exist.

Someone may want to talk to the DRPA, which installed this very type of zipper barrier over 5 years ago on the Walt Whitman Bridge (linking Philly & South Jersey).  Other versions have been used for many years before that.

It's also a bit of overkill to close the entire highway to install it. The same thing can be accomplished over a few nights, just closing a lane or 2 in each direction.

[myosh_tino]

It's also a bit of overkill to close the entire highway to install it. The same thing can be accomplished over a few nights, just closing a lane or 2 in each direction.

I suspect the full closure is needed so bridge crews can restripe the roadway.  Currently the middle 4 lanes are only 10 ft wide while the outside, or curb, lanes are 11 ft wide.  If the barrier is 1 ft wide and no restriping is done, the lanes adjacent to the barrier would only be 9 1/2 feet wide.

[roadfro]

It's also a bit of overkill to close the entire highway to install it. The same thing can be accomplished over a few nights, just closing a lane or 2 in each direction.

I suspect the full closure is needed so bridge crews can restripe the roadway.  Currently the middle 4 lanes are only 10 ft wide while the outside, or curb, lanes are 11 ft wide.  If the barrier is 1 ft wide and no restriping is done, the lanes adjacent to the barrier would only be 9 1/2 feet wide.

In fact, one of the last paragraphs in the article says the closure is needed to remove the tollbooths and restripe the roadway.

[jeffandnicole]

It's also a bit of overkill to close the entire highway to install it. The same thing can be accomplished over a few nights, just closing a lane or 2 in each direction.

I suspect the full closure is needed so bridge crews can restripe the roadway.  Currently the middle 4 lanes are only 10 ft wide while the outside, or curb, lanes are 11 ft wide.  If the barrier is 1 ft wide and no restriping is done, the lanes adjacent to the barrier would only be 9 1/2 feet wide.

In fact, one of the last paragraphs in the article says the closure is needed to remove the tollbooths and restripe the roadway.

Roadways are restriped all the time (think construction zones) without the roadway needing to be shut down. Why are they removing four tollbooths?

[TheStranger]

It's also a bit of overkill to close the entire highway to install it. The same thing can be accomplished over a few nights, just closing a lane or 2 in each direction.

I suspect the full closure is needed so bridge crews can restripe the roadway.  Currently the middle 4 lanes are only 10 ft wide while the outside, or curb, lanes are 11 ft wide.  If the barrier is 1 ft wide and no restriping is done, the lanes adjacent to the barrier would only be 9 1/2 feet wide.

In fact, one of the last paragraphs in the article says the closure is needed to remove the tollbooths and restripe the roadway.

Roadways are restriped all the time (think construction zones) without the roadway needing to be shut down. Why are they removing four tollbooths?

- The Golden Gate Bridge has had the same 6 lanes since 1937, with no shoulder.  Very little right of way to work with.  In theory they could try to leave one lane open in each direction while doing much of the work in the middle, seems though that a full closure was considered more efficient.

- Current GGB toll plaza does not leave much room for the barrier-moving vehicle to maneuver in.  Here's what the setup looks like right now, looking southbound:

https://maps.google.com/maps?q=Golden+Gate+Bridge&hl=en&ll=37.807387,-122.475828&spn=0.001731,0.003747&sll=37.807387,-122.475828&sspn=0.001738,0.003747&t=m&z=19&layer=c&cbll=37.807387,-122.475828&panoid=2k8jJHxG3Xb2vh7UNdcjUQ&cbp=12,111.07,,0,-0.29

[jakeroot]

It's also a bit of overkill to close the entire highway to install it. The same thing can be accomplished over a few nights, just closing a lane or 2 in each direction.

I suspect the full closure is needed so bridge crews can restripe the roadway.  Currently the middle 4 lanes are only 10 ft wide while the outside, or curb, lanes are 11 ft wide.  If the barrier is 1 ft wide and no restriping is done, the lanes adjacent to the barrier would only be 9 1/2 feet wide.

In fact, one of the last paragraphs in the article says the closure is needed to remove the tollbooths and restripe the roadway.

Roadways are restriped all the time (think construction zones) without the roadway needing to be shut down.

If they left even one lane open in each direction, most people wouldn't avoid the bridge in the same way that they would should the bridge be completely closed. Most people will just stay home during this time. If the bridge was left open, 90% of people would keep their plans, and huge traffic jams would ensue.

That's just a hunch, mind you.

[myosh_tino]

- The Golden Gate Bridge has had the same 6 lanes since 1937, with no shoulder.  Very little right of way to work with.  In theory they could try to leave one lane open in each direction while doing much of the work in the middle, seems though that a full closure was considered more efficient.

While the Golden Gate Bridge has always been 6 lanes, originally all 6 lanes were 10 ft wide.  According to the bridge district's website, the curb lanes were widened by 1 ft around 1984 when the road deck was replaced giving us the current 11 ft outside lanes and 10 ft inner lanes.

I also agree that a full closure was the right call considering all that will be happening on the bridge during those 52 hours (installing moveable barrier, removing toll booths and restriping the roadway.

[Alps]

Barriers are 2 feet wide, so figure it'll be 10-foot lanes all round. A full bridge closure is best to actually put the barrier out across the bridge. At a minimum, it would take closing the center two lanes and having a lot of equipment shuttling back and forth. I'm sure the pros of a full overnight bridge closure vastly outweigh the cons in terms of constructability and cost.

[myosh_tino]

Barriers are 2 feet wide, so figure it'll be 10-foot lanes all round. A full bridge closure is best to actually put the barrier out across the bridge. At a minimum, it would take closing the center two lanes and having a lot of equipment shuttling back and forth. I'm sure the pros of a full overnight bridge closure vastly outweigh the cons in terms of constructability and cost.

Actually, the barrier being installed on the Golden Gate Bridge is only going to be 1 ft wide.

[kkt]

It's also a bit of overkill to close the entire highway to install it. The same thing can be accomplished over a few nights, just closing a lane or 2 in each direction.

I suspect the full closure is needed so bridge crews can restripe the roadway.  Currently the middle 4 lanes are only 10 ft wide while the outside, or curb, lanes are 11 ft wide.  If the barrier is 1 ft wide and no restriping is done, the lanes adjacent to the barrier would only be 9 1/2 feet wide.

In fact, one of the last paragraphs in the article says the closure is needed to remove the tollbooths and restripe the roadway.

Roadways are restriped all the time (think construction zones) without the roadway needing to be shut down. Why are they removing four tollbooths?

The bridge changed about a year ago to all electronic tolling.  This is probably as good a time as any to remove the booths.

[briantroutman]

In fact, one of the last paragraphs in the article says the closure is needed to remove the tollbooths and restripe the roadway.

Roadways are restriped all the time (think construction zones) without the roadway needing to be shut down. Why are they removing four tollbooths?

The bridge changed about a year ago to all electronic tolling.  This is probably as good a time as any to remove the booths.

They're not removing the toll plaza, unfortunately, only shedding two of its eleven lanes. The image below shows the final result, as taken from the GGBHTD's Visual Impact Assessment. (http://goldengatebridge.org/projects/documents/Visual_Impact_Assessment_GGB_MMB.pdf)

The three innermost plaza lanes will be replaced by taller and wider lanes designated for trucks and busses–a complete reverse of the current traffic pattern and thus creating a perpetual weaving motion where the largest, slowest vehicles in the rightmost lane of the bridge are trying to move to the leftmost lane at the toll plaza (and vice versa higher speed cars).

The zipper barrier will be permanently snaked around the east side of the toll plaza building (the current "WIDE LANES"  pass through).

[kkt]

In fact, one of the last paragraphs in the article says the closure is needed to remove the tollbooths and restripe the roadway.

Roadways are restriped all the time (think construction zones) without the roadway needing to be shut down. Why are they removing four tollbooths?

The bridge changed about a year ago to all electronic tolling.  This is probably as good a time as any to remove the booths.

They're not removing the toll plaza, unfortunately, only shedding two of its eleven lanes. The image below shows the final result, as taken from the GGBHTD's Visual Impact Assessment. (http://goldengatebridge.org/projects/documents/Visual_Impact_Assessment_GGB_MMB.pdf)

The three innermost plaza lanes will be replaced by taller and wider lanes designated for trucks and busses–a complete reverse of the current traffic pattern and thus creating a perpetual weaving motion where the largest, slowest vehicles in the rightmost lane of the bridge are trying to move to the leftmost lane at the toll plaza (and vice versa higher speed cars).

The zipper barrier will be permanently snaked around the east side of the toll plaza building (the current "WIDE LANES"  pass through).

That's crazy!  Why have toll booths if all the toll collection is electronic and by mail?  Why put the bigger booths in the left lanes when the right lanes on the bridge are wider for bigger vehicles?  The bridge district should be sharing whatever it is they're smoking!

[TheStranger]

That's crazy!  Why have toll booths if all the toll collection is electronic and by mail?  Why put the bigger booths in the left lanes when the right lanes on the bridge are wider for bigger vehicles?  The bridge district should be sharing whatever it is they're smoking!

I wonder if it's for historic reasons (given most of the tollbooths that will remain still date back to the bridge's 1936 opening).

[SimMoonXP]

Here is the 1962 map of Golden Gate Bridge on Page 15 B2 to B3. The adjacent of Golden Gate Bridge are: Presidio of San Francisco, US-101 at Marin County, Marina Section of San Francisco, Alcatraz Island (home of former Prison), was functional in back in 1962!

[briantroutman]

That's crazy!  Why have toll booths if all the toll collection is electronic and by mail?  Why put the bigger booths in the left lanes when the right lanes on the bridge are wider for bigger vehicles?  The bridge district should be sharing whatever it is they're smoking!

I wonder if it's for historic reasons (given most of the tollbooths that will remain still date back to the bridge's 1936 opening).

I'm sure preservationism has everything to do with it. This is the same GGBHTD that made an exact replica of the analog clock over the toll plaza to replace one that had been there for 50 years and was falling into disrepair. This clock is also available pictured on T-shirts in the official gift shop, by the way.

This is also the same GGBHTD that went engineer shopping in the '60s to buy a report stating that suspending BART tracks from the bridge would cause damage to the structure (though other independent studies suggested otherwise). I can't help but think they see themselves as being, not in the transportation infrastructure business, but in the "yup, that's the famous Golden Gate Bridge–and it's ours"  business.

Unfortunately, this means that even more bemused families in rented Caravans will come to a complete stop at the completely needless toll plaza and cause near-misses and rear-end collisions.

Alcatraz Island (home of former Prison), was functional in back in 1962!

It closed the following year.

[myosh_tino]

That's crazy!  Why have toll booths if all the toll collection is electronic and by mail?  Why put the bigger booths in the left lanes when the right lanes on the bridge are wider for bigger vehicles?  The bridge district should be sharing whatever it is they're smoking!

Here's my theory...

The current configuration on the bridge is 11 ft outside lanes (a.k.a. the "curb" lanes) and the middle 4 lanes are 10 ft wide.  If the moveable median barrier (MMB) is installed on the bridge with no changes to the lane widths, the lanes on either side of the MMB would only be 9 1/2 feet wide because the MMB itself is 1 foot wide.

Therefore I believe the lane width configuration will change so the outside 4 lanes will be 10 feet wide and the inner two lanes will be 11 ft wide.  When the bridge is in a 3/3 configuration (3 north, 3 south), the inner two lanes will be 10.5 ft wide, all other lanes will be 10 ft wide.  When the bridge is in a 4/2 configuration (2 one direction, 4 in the other) the side with 2 lanes will have two 10 ft lanes while the other side will have lane widths of 10 ft, 11 ft, 10 ft and 10 ft starting with the lane closest to the MMB.

In either configuration, the wide lanes will be in the middle of the bridge so it's possible that trucks will be encouraged to use the middle lanes on the bridge rather than the far right lane.  That might explain why the toll plaza is being reconfigured to put the bigger lanes on the left.

Here's a quick drawing that tries to illustrate what I said above...

[jakeroot]

In either configuration, the wide lanes will be in the middle of the bridge so it's possible that trucks will be encouraged to use the middle lanes on the bridge rather than the far right lane.  That might explain why the toll plaza is being reconfigured to put the bigger lanes on the left.

[TheStranger]

A side note to that Golden Gate Bridge map: El Camino Del Mar is still shown as open on the cliffside segment northeast of the Palace of the Legion of Honor that had been closed permanently (due to landslides) ca. 1957.

[myosh_tino]

Here's my theory...

The current configuration on the bridge is 11 ft outside lanes (a.k.a. the "curb" lanes) and the middle 4 lanes are 10 ft wide.  If the moveable median barrier (MMB) is installed on the bridge with no changes to the lane widths, the lanes on either side of the MMB would only be 9 1/2 feet wide because the MMB itself is 1 foot wide.

Therefore I believe the lane width configuration will change so the outside 4 lanes will be 10 feet wide and the inner two lanes will be 11 ft wide.  When the bridge is in a 3/3 configuration (3 north, 3 south), the inner two lanes will be 10.5 ft wide, all other lanes will be 10 ft wide.  When the bridge is in a 4/2 configuration (2 one direction, 4 in the other) the side with 2 lanes will have two 10 ft lanes while the other side will have lane widths of 10 ft, 11 ft, 10 ft and 10 ft starting with the lane closest to the MMB.

In either configuration, the wide lanes will be in the middle of the bridge so it's possible that trucks will be encouraged to use the middle lanes on the bridge rather than the far right lane.  That might explain why the toll plaza is being reconfigured to put the bigger lanes on the left.

Here's a quick drawing that tries to illustrate what I said above...

Now that the moveable median barrier has been installed on the Golden Gate Bridge, I thought I would point out that all of my theories in the above post were 100% WRONG! 

According to news reports, the lane widths were NOT changed when the MMB was installed.  The outside 2 lanes are still 11 feet wide while the inner 4 lanes are 10 feet wide.  This means the lane on either side of the MMB is only 9 1/2 feet wide!    Kinda narrow don't cha think?

[roadfro]

That is probably one reason why they lowered the speed limit on the bridge...

[myosh_tino]

That is probably one reason why they lowered the speed limit on the bridge...

They lowered the speed limit on the Marin approach to the bridge from 55 MPH to 45 MPH.  The speed limit on the bridge itself has always been 45 MPH.

[TheStranger]

The speed limit on the bridge itself has always been 45 MPH.

If I'm not mistaken, it was 55 MPH until the 1980s.  (Though I don't know what the speed limit was like prior to the plastic cone barrier era)