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SR 99 Aurora Bridge Fence - Common Questions

What is WSDOT doing to deter suicides on the Aurora Bridge?

Construction is underway on a safety fence to deter people from jumping off of the bridge. This effort follows the city of Seattle’s installation of signs and phones on the Aurora Bridge in 2006 to connect people directly to a suicide hotline.

Why is deterring suicides from the Aurora Bridge a priority for WSDOT?

Improving safety is a top priority for WSDOT. The issue of suicides on the Aurora Bridge has a wide range of effects. We’re concerned for the well being of those who consider suicide and the aftermath of suicides on their friends and families. Deterring suicides also protects the growing number of people who live, work and travel below the bridge. These people are at risk of physical harm when someone jumps from the bridge and are often traumatized by experiencing the aftermath of suicide attempts.

Deterring suicides also enhances safety for emergency responders, including those who must make emergency dives into the murky and debris-filled waters of the Ship Canal to save people who jump from the Aurora Bridge, and for those who often risk their lives trying to restrain people from jumping.

Fence construction answers

What is the construction schedule?
  • In September 2009 WSDOT awarded the construction contract to Massana Construction, who submitted the low bid of $2.9 million.
  • Preliminary construction began in May 2010. Fence construction began in June 2010, when crews start drilling holes for the fence's anchor bolts.
  • The fence will be complete in early 2011.
  • Crews will mostly work Sunday through Thursday nights, 9 p.m. to 5 a.m., however, we also expect some construction to occur on weekends, mostly on Sunday.
How will crews install the fence?

Since most of us have never built a bridge fence, the best way to explain it is to compare it to something that most people can relate to. Fortunately, the process for installing the fence is very similar to putting up shelving on a wall in your home. Let's compare:

Shelving Bridge fence
Use a stud finder to scan your wall to determine where you can safely drill. Use an x-ray scanner on bridge deck to determine where you can safely drill.
Measure and mark drill hole locations Measure and mark drill hole locations
Drill holes for anchor bolts Either a) drill holes for anchor bolts or b) remove existing rivets and enlarge the rivet hole to fit the anchor bolt.
Insert anchor bolts and mount shelf bracket Insert anchor bolts and mount fence bracket
Mount and secure shelf on bolts and brackets Mount and secure fence on bolts and brackets


How will construction affect traffic?

  • When crews work at night on the west side of the bridge, they will close two southbound lanes and the adjacent sidewalk. One lane will remain open.
  • When crews work at night on the east side of the bridge, they will close two northbound lanes and the adjacent sidewalk. One lane will remain open.
  • When crews during the day, they may close lanes on city streets under the bridge and restrict some street parking. Daytime work on the bridge will be done between the morning and afternoon commute and close a single lane and the adjacent sidewalk.
  • We will post regular lane closure updates on our Web site so you can know what's closed and when.

What will cause construction noise ?

Neighbors will hear the loudest noise starting in July when crews begin removing rivets from the side of the bridge (the rivets will be replaced with fence post anchor bolts). Other noise sources include drills and portable generators.

What is WSDOT doing to reduce construction noise?

Just the word, "drilling" sounds noisy, but it will be done using a fixture that suppresses noise.In addition, the generators will be encased in foam-lined steel boxes.

Rivet removal is more challenging.We are looking at ways to reduce the noise effects of rivet removal.

Will I hear construction noise at night?

We expect noise effects to be felt by those living beneath or near to the bridge. This distance will vary depending on noise source (rivet removal noise will travel farther) topography and the type of obstructions between the work site and nearby residences. For example, thick vegetation such as multiple stands of trees and bushes, hills, and buildings help to block or absorb sound, while water amplifies it.

Another factor is line of sight. If you can see what is producing a sound, it will sound louder than if you can't see it.

Why does construction noise sound louder at night?

The absence or reduction of background noise from traffic, work and other daytime activities may cause construction noise to sound louder at night.

An example of this effect is the volume on your car radio. When you get on the freeway, you have to turn the volume up because the traffic noise masks the sound of the radio. When you get off the freeway and stop at a traffic light , the same volume level is much too loud and you have to turn it down. The same principle applies to how people perceive nighttime construction noise.

Fence design

How will crews install the fence?

The fence will be installed on the outside of the bridge. Since jet packs for construction workers haven't been invented yet, contractors must use bucket trucks, and customized work platforms that are extended up and over the side of the bridge.

Why fencing?

Adding fencing to the bridge is the most cost effective and practical answer to deter people from falling from the bridge. Fencing has these advantages:

  • A successful record of deterring suicides on bridges and other elevated structures.
  • Lower maintenance cost over its life cycle compared to other deterrent options.
  • Preserves existing bicycle and pedestrian routes.  
WSDOT look at netting to deter suicides?

We examined netting and determined that netting is not feasible because it would:

  • Impede inspections of the underside of the bridge.
  • Catch trash and birds, requiring frequent and maintenance to clear debris.
  • Need to be replaced on a regular basis.
  • Present unique challenges for emergency personnel responding to suicide attempts.
Officials chose a net for the Golden Gate Bridge's proposed suicide deterrence project. Why is a net feasible for the Golden Gate Bridge and not the Aurora Bridge?

The Golden Gate Bridge is suspension bridge with many of the key structural components close to or above the roadway surface. The Aurora Bridge is a cantilever truss bridge with the key structural components completely below the roadway surface. On the Golden Gate Bridge, a net 20 feet below the sidewalk does not restrict the ability of inspection and maintenance crews to access structural components. On the Aurora Bridge, a similar net would severely impede inspection and maintenance operations, and block access by an under bridge inspection truck (UBIT).

The Golden Gate Bridge extends over water and unpopulated land. More than two thirds of the Aurora Bridge extends over residential and commercial areas. A net extending 20 feet below and 20 feet outside of the bridge would be in lateral and vertical conflict with many structures. In addition, the “visual footprint” of the bridge would become significantly larger when viewed from neighborhoods below the bridge.

Why does the Golden Gate Bridge net option have lower maintenance costs than Golden Gate fence options?

The fence options proposed for the Golden Gate Bridge had different characteristics than the proposed Aurora Bridge fence. WSDOT is proposing an eight foot nine inch fence made of identical removable panels. The Golden Gate Bridge fence options were 10-12 feet tall, not removable, and incorporated glass lookout areas. Because the Golden Gate fence options were tall and fixed in place, special gates, safety harnesses, and new walkways would be needed to access areas behind the fence. This is a departure from the way the maintenance staff currently uses to access the Golden Gate Bridge, and is estimated to add over three hours per day in lost productivity for their maintenance crew.

Maintenance and inspections on the Aurora Bridge are accomplished through the use of a UBIT, which has an arm that extends over and below the bridge. We are designing our proposed fence so the ability to access the bridge with a UBIT would not change. In cases of special inspection or maintenance needs, fence panels could be temporarily removed from our fence to allow unrestricted access.

The use of clear panels in the Golden Gate Bridge fence options also required a heavy amount of cleaning to remove grime and sea spray, which added labor and equipment cost to the maintenance estimate.

Why not close the bridge to pedestrians?

The city of Seattle, and bicycle and pedestrian advocacy groups oppose this idea. WSDOT is particularly concerned that closing the sidewalk may encourage bicyclers to ride in traffic lanes, which would increase the risk of collisions. Pedestrians (and bicyclists not wishing to ride in a travel lane) would either have to board a transit bus to cross the bridge or detour to the Fremont Bridge. As a result, the idea is not feasible.

What about moving the sidewalks underneath the bridge, as recommended in the SR 99 Route Development Plan?

The SR 99 Route Development Plan recommended wider travel lanes on the bridge along with a median barrier to physically separate opposing traffic. This option would provide an enclosed structure attached underneath the Aurora Bridge for pedestrian and bicycle travel. However, this conceptual project is outside the scope of the current project and would present these challenges:

  • Construction cost. The conceptual project would require a significant investment from the Legislature, perhaps more than double the $29 million estimate provided in the RDP due to inflation in labor costs and materials.
  • Public safety. Pedestrians and bicyclists on an under-the-bridge walkway would not be visible from vehicles on the bridge. This could encourage crime, and require safety and security measures, such as escape ladders and surveillance cameras.
  • Aesthetics. The Aurora Bridge is listed on the National Register of Historic Places. A walkway suspended underneath the bridge would need to garner the support of the community and must be approved by city and state preservation boards.
  • Maintenance and inspection issues. Ongoing maintenance and regular inspections would be difficult and costly since walkways are separate structures.
The fence will only be 8 feet 9 inches above the sidewalk to allow for bridge inspections. How can you prevent people from getting over the fence by climbing first onto the outer railing?

Our designers examined alternatives that would deter successful fence climbing. Our final design incorporates pickets that will substantially reduce the chance of being able to get a hand or foothold near the top of the fence.

How can you ensure that the fence will effectively deter suicides?

Research indicates that just having a barrier in place is an effective deterrent for individuals who wish to attempt suicide by jumping. There is evidence that suicides by jumping off tall structures are highly impulsive acts, sometimes with only seconds between the impulse and the jump. Barriers make jumping more difficult and buy time for reconsideration or intervention by others. Along with physical design features that make the fence hard to climb, we designed the fence with the concept of face validity in mind. Face validity is the impression that it would take considerable effort to overcome the fence.

Even if the fence is an effective deterrent, won’t people go elsewhere to commit suicide?

That is a common perception; however, studies show otherwise. For example, a 1978 University of California Berkeley study of 500 people who were stopped from jumping off the Golden Gate Bridge showed that only about six percent went on to commit suicide in some other way. In another study, researchers looked at two bridges a block apart in Washington, D.C. After fencing was installed on the Duke Ellington Bridge, they found no corresponding increase in the number of suicides on the nearby Taft Bridge.

Can the bridge can support the extra weight of a fence?

An important consideration of any bridge alteration is where additional weight is placed. Weight placed in the center or roadway deck (the flat piece that vehicles travel on) of the bridge would have a different impact than weight added to the edge of the bridge.

For example, adding weight to the deck of the bridge may exceed the maximum weight that the deck was designed to carry, which would require significant structural reinforcement. However, the bridge can safely support the added weight of the concrete and steel pedestrian barrier on the edges of the bridge because the additional weight is supported by large steel girders instead of by the roadway deck. The weight of a new fence would be supported similarly.

Our bridge engineers reviewed the data, ran preliminary calculations, and gave the go-ahead to start design. Following recommendations released by FHWA after the I-35 bridge collapse in Minnesota, we conducted a detailed analysis of how additional weight affects specific bridge components, and verifed the bridge’s capacity to carry the weight of the fence. The results from that analysis showed the bridge can support the additional weight.

Why are you using vertical steel rods in your design?

We wanted an effective fence. Following guidance on design of safety barriers, we eliminated horizontal elements from consideration because they can be perceived as easy to climb. Mesh and diagonal elements may send a similar message. Steel rods are also very light both in terms of weight and in visual appearance.

Why didn’t WSDOT formally involve the community as you developed a cost estimate and looked at alternatives to fencing?

We developed our cost estimate in response to a request from the Legislature. That request specifically asked WSDOT to estimate costs for fencing. Although we investigated other options, such as netting and closing the bridge to pedestrian, neither alternative was feasible for the reasons described above.

Why did WSDOT form a citizen’s advisory committee for this project?

The Aurora Bridge is a designated City of Seattle landmark and listed on the National Register of Historic Places. The committee helped ensure our fence design reflected community values and issues, complemented the bridge and surrounding landscape, and met the permit requirements of the City of Seattle’s Landmarks Preservation Board and the Washington State Department of Archaeology and Historic Preservation. Establishing an advisory committee is an integral part of a concept known as Context Sensitive Design.

What is Context Sensitive Design?

Context sensitive design (CSD) is a process that broadens the focus of project development to look beyond the basic transportation issues, and develop projects that are integrated with the unique contexts of the project setting. The CSD concept is a collaborative effort that obligates the participants to understand the effects and trade-offs associated with project decisions.

We also formed a technical design committee that provided input to the WSDOT design team. The technical design committee was comprised of citizen architects and experts in historic preservation and bridge design. The design team integrated the recommendations and values of the advisory committees into the fence design.

Did the advisory committee choose the fence design?

No. WSDOT chose the preliminary design we submitted to the Landmarks Preservation Board. However, the advisory committee played a vital role in the development of fence designs and identification of a preferred design for board review.

Project budget

How much will the project cost?

The original budget for the project was $8.1 million. In September 2009, we revised the budget to 4.6 million. The budget includes $1 million for design and $3.6 million for construction.

Why is the cost lower than you originally estimated?

This lower cost is mainly due to three factors: 1) more competitive private contractor bidding climate, 2) removal of new street lighting from the project, and 3) lower steel prices.

Still, why does it cost $3.6 million to build a fence?

As you might expect, our construction budget includes the costs for fence materials and fabrication. However, the budget also includes state and local sales tax, and funds these activities that a contractor needs to perform to successfully complete the job:

  • purchasing and transporting construction materials and equipment.
  • hiring, training, paying, and providing benefits for skilled workers to erect the fence.
  • providing safety measures or constructing platforms to ensure worker safety when attaching the fence.
  • traffic control devices and staff to keep traffic moving during construction and keep workers safe.
  • erosion and sediment control.
  • daily inspection of construction work and contract administration to ensure the fence is built to our specifications.
Why not spend project funds on suicide prevention measures instead, such as mental health counseling and education campaigns?

This project is funded through the gas tax. The 18th amendment to the Washington State Constitution dedicates gas taxes to highway purposes.

Wait, I still have more questions.

No problem, just send us an e-mail or call 206-805-2862