COMMISSION 
AGENDA MEMORANDUM                        Item No.          10b 
ACTION ITEM                            Date of Meeting    September 28, 2021 
DATE:     September 17, 2021
TO:        Stephen P. Metruck, Executive Director 
FROM:    Laurel Dunphy, Director Airport Operations 
Wayne Grotheer, Director Aviation Project Management 
SUBJECT:  Widen Arrivals Roadways (CIP #C800866) 
Amount of this request:               $6,900,000 
Total estimated project cost:         $79,300,000 
ACTION REQUESTED 
Request Commission authorization for the Executive Director to (1) advertise and award a
major public works contract for the early demolition of the fourth-floor bridge to the main
parking garage, (2) amend existing service agreement for Airport Roadway Design Support
Services with HNTB, in the amount of $3,100,000, with a new contract total of $8,700,000 (3)
enter into a reimbursable agreement with the Federal Aviation Administration, and (4) authorize
an additional $6,900,000 for a total project authorization of $15,500,000 for the Widen Arrivals
Roadways project at Seattle-Tacoma International Airport. 
EXECUTIVE SUMMARY 
This authorization will allow for (1) the early demolition of the fourth-floor bridge to the main
parking garage. The demolition scope was previously included in the project but is being
advanced to take advantage of schedule improvements and reduced traffic volumes due to the
pandemic. (2) The budget for the service agreement for Airport Roadway Design Support Services
with HNTB, will be increased to cover all the design costs and as the project scope has expanded
so has the need to increase this contract. This authorization will provide an additional $3,100,000
to cover 90 percent through construction design costs. (3) While not fully defined at our current
design level the project has identified a Federal Aviation Administration duct bank within the
project limits. This authorization will allow the port to enter into a reimbursable agreement if
needed, to cover any FAA cost resulting from that agency's project support. (4) Authorization for
the additional $6,900,000 includes the $3,100,000 design service increase for HNTB, $1,800,000
to fund the bridge demo construction, $200,000 to transfer to the art pool and the remaining
$1,800,000 for port engineering and soft costs associated with the project increase. 


Template revised January 10, 2019.

COMMISSION AGENDA  Action Item No. 10b                                 Page 2 of 8 
Meeting Date: September 28, 2021 
JUSTIFICATION 
This project supports the following Century Agenda strategic goals and objectives: 
1)  Advance this region as a leading tourism destination and business gateway by meeting the
region's air transportation needs by delivering vital facilities and infrastructure  in a
sustainable and cost-effective manner. 
2)  Be the greenest and most energy efficient Port in North America by meeting or exceeding
agency requirements for storm water leaving Port-owned or operated facilities. 
3)  Be a model for equity, diversity, and inclusion by increasing utilization of Women and
Minority Business Enterprise (WMBE) and Disadvantage Business Enterprise (DBE) DBE firms
and eliminate disparity of access to opportunities. 
The terminal roadway system was originally designed in 1968 to support an overall activity level 
of 25 million annual passengers (MAP). Over the years several efforts have been completed to
extend the life of the terminal roadway system. These include relocating commercial ground
transportation services to the third floor Ground Transportation Center and Northeast Ground
Transportation Lot, extending the Arrivals curbside to the south for public transit and commercial
ground transportation, and relocating rental car customers off-site to the consolidated Rental
Car Facility. 
Approximately 51.8 million passengers used the airport in 2019, and Arrivals experienced 
recurring congestion at peak travel times on a daily basis.1  Widening of roadways accessing
Arrivals and the Main Garage will improve access to parking, ground transportation center, and
curbsides by alleviating congestion and reducing queuing on the main roadway entrances for
airport visitors and passengers. The project will enhance roadway safety to accommodate the
existing passenger activity. With no improvements, studies have indicated that the queueing on
the Northern Airport Expressway will reach the I-5/I-405 South Center interchange on a regular
basis during the summer months. 
Diversity in Contracting 
The design of this project is under an existing project specific contract to support both the Air
Cargo Road Safety Improvements and Widen Arrivals Roadways projects. That contract has a 
Small Business Enterprise (SBE) goal of 20% (this contract was executed prior to our Diversity in
Contracting program). The firm's current SBE utilization is 20.2 percent. The 20% goal assumed
that the consultant would be completing all the design work. Since execution, it was decided to
perform both structural and stormwater design internally. This has reduced the opportunity for
the consultant to meet the original goal. Currently the contract has a participation of 17.5% for
1 SEA has seen a dramatic reduction in passenger volumes as a result of the COVID-19 public health emergency. In
2020, passenger volumes were approximately 60 percent below 2019 levels. Based on airlines schedules, COVID-19
public health emergency travel restrictions, airline service announcements, and consultation with airline and travel
industry sources, it is estimated the Airport will reach 2019 passenger volumes around 2024. While there is still
uncertainty in full recovery of the impacts related to the COVID-19 public health emergency, current data is showing
that recovery is beginning as airport passenger volumes increase at SEA and beyond. 

Template revised June 27, 2019 (Diversity in Contracting).

COMMISSION AGENDA  Action Item No. 10b                                 Page 3 of 8 
Meeting Date: September 28, 2021 
the Widen Arrivals Roadways portion of the contract, and 20.6% for the Air Cargo Road Safety
Improvements portion of the contract. 
The project team will  work with the Diversity in Contracting Department to determine
participation opportunities and will set appropriate aspirational goals for WMBE participation in
both construction contracts. 
DETAILS 
The Widen Arrivals Roadways project includes the widening of the southbound lanes of the
Northern Airport Expressway to provide an additional two lanes for a total of six lanes from South
170th Street into the Departures and Arrivals curbsides and Main Garage. This requires the
relocation and expansion of the roadways to the west given the location of the columns
supporting the Light Rail Transit guideway. In addition to the improvements described above, the
project will relocate the north rental car bus curb further north to increase utilization of the
Arrivals curbside, demolish the fourth-floor bridge from Departures to the Main Garage that was
closed with the construction of the light rail transit walkway, and complete the structural
improvements at the north end of the Service Tunnel. The scope of work for this project has
increased to include additional utility relocations and the renewal of utility infrastructure
impacted by the project. 
This project will support multiple objectives in the Century Agenda by improving access and
decreasing congestion entering the airport. A byproduct of reduced congestion is a decrease in
emissions from vehicles in traffic. 
The contract amendment will support additional design associated with the increased project
scope. On July 11, 2017, Port Commission (Commission) authorized the execution of a project
specific contract to support both the Air Cargo Road Safety Improvements and Widen Arrivals
Roadways projects in the amount of $3,000,000. The original contract included funding for Air
Cargo Road Safety Improvements and the original single-lane widening scope for Widen Arrivals
Roadways. On January 22, 2019, the Commission authorized the amendment to increase the
funding for this contract by $2,600,000, with a new contract total in the amount of $5,600,000.
This amendment and increase supported the project scope change from a single-lane widening 
to a double-lane widening project. With this amendment request, the funding for this contract
would increase by an additional $3,100,000, for a new contract total in the amount of $8,700,000. 
On April 24, 2018, the Commission authorized the Airport Utilities Master Plan which has resulted
in a plan to build a utility corridor under the airport roadway system, and to replace or upgrade
existing airport utility infrastructure. The Widen Arrivals Roadways project will relocate a number
of existing utility systems in order to shift the roadways west. The utility system scope has been
expanded to include the replacement of existing utility infrastructure that has reached the end
of its useful life. Utility infrastructure capacity improvements associated with the SAMP nearterm
projects, including the planned utility corridor, are not included as part of the Widen Arrivals
Roadways project. 

Template revised June 27, 2019 (Diversity in Contracting).

COMMISSION AGENDA  Action Item No. 10b                                 Page 4 of 8 
Meeting Date: September 28, 2021 

The project scope and budget has increased from $50 million to $79.3 million. The majority of
the budget increase, approximately $18 million, is associated with the shifting of the alignment
further to the west to accommodate potential future projects, specifically the realignment of the
southbound lanes of the Northern Airport Expressway and the utility corridor. Approximately $3
million is associated with the replacement of existing utility infrastructure that has reached the
end of its useful life. Approximately $3 million is associated with refinements to existing scope 
including additional variable message signs to support operations, and passenger enhancements
to the rental car bus curb. The remaining $5.3 million is associated with other construction costs,
including mobilization, traffic control, and erosion control, that also increase when the overall
construction scope increases. 
The project will be delivered through two design-bid-build major works contracts.  The first
contract will include the early demolition of the fourth-floor bridge between Departures and the
Main Garage. The second contract will complete the roadway realignment, lane additions, and
utility  system  infrastructure  improvements  and  will  utilize  a  project  labor  agreement.  By
completing the early demolition work the total contract time is reduced for the second contract
reducing associated construction phase soft costs. 
On June 14, 2021, the Port of Seattle issued a determination of non-significance for the Widen
Arrivals Roadways project. A State Environmental Policy Act (SEPA) checklist was completed and
was the basis for that determination. 
Art is planned to be incorporated within this project. This request includes the authorization of
$200,000 to support the selection and placement of art within the project. The project's total
allocation for art is estimated at $780,000.  The remaining balance will be requested with the
future construction authorization. 
Scope of Work 
The Widen Arrivals Roadway project is a roadway improvement project. These types of projects
generally include paving, sidewalks, barriers/curbs, pavement markings, illumination, storm
drainage, retaining walls, signage, sign structures, safety elements (e.g. attenuators), and
Intelligent Transportation Systems (ITS) improvements. Key components of the project include: 
1)  The widening of the southbound lanes of the Northern Airport Expressway to provide two 
additional lanes into the curbsides and Main Garage 
2)  The demolition of the existing closed bridge from Departures to the fourth floor of the Main
Garage 
3)  The demolition of the remaining Bridge 5 ramp and abutment, construction of a retaining
wall to support the Departures approach roadway, and the relocation of the north rental car
bus curb further to the north 
4)  The completion of the seismic retrofit of the north portal of the Service Tunnel, consistent
with work completed in other portions of the tunnel 

Template revised June 27, 2019 (Diversity in Contracting).

COMMISSION AGENDA  Action Item No. 10b                                 Page 5 of 8 
Meeting Date: September 28, 2021 
5)  The construction of a retaining wall along the airfield north of the Service Tunnel and the
relocation of communications, power, water, and natural gas utility infrastructure systems 
6)  The replacement of additional power and water utility infrastructure systems that are past
their useful life 
7)  The relocation of a portion of Air Cargo Road along the new airfield retaining wall, and the
Departures and Arrivals approaches further to the west to accommodate the two additional
lanes 
Schedule 
Early Work: Bridge Demo 
Design complete                                                       2021 Quarter 4 
Construction start                                                           2022 Quarter 2 
In-use date                                                                  2022 Quarter 3 
Widen Arrivals Approach 
Design complete                                                       2022 Quarter 4 
Commission construction authorization                                   2023 Quarter 1 
Construction start                                                           2023 Quarter 2 
In-use date                                                                  2025 Quarter 4 
Cost Breakdown                                     This Request           Total Project 
Design                                                 $4,900,000            $14,400,000 
Construction                                            $1,800,000            $64,120,000 
Art (Transfer to Art CIP)                                       $200,000                $780,000 
Total                                                        $6,900,000             $79,300,000 
ALTERNATIVES AND IMPLICATIONS CONSIDERED 
Alternative 1  No improvements are completed until the Sustainable Airport Master Plan
(SAMP) near-term project relocates the southbound lanes to support the development of the
second terminal. The Widen Arrivals Roadways improvements would be completed with the
SAMP near-term projects.
Cost Implications: $0 
Pros: 
(1)   No significant capital investment in the short-term 
Cons: 
(1)   Due to existing capacity constraints significant congestion and queueing occurs each
day on the southbound lanes of the Northern Airport Expressway. Delay times are
anticipated to exceed 25 minutes 
(2)   Bridge remains that overloads the Service Tunnel structure, reducing the useful life of
the Service Tunnel 

Template revised June 27, 2019 (Diversity in Contracting).

COMMISSION AGENDA  Action Item No. 10b                                 Page 6 of 8 
Meeting Date: September 28, 2021 
This is not the recommended alternative. 
Alternative 2  Widening of the southbound lanes of the Northern Airport Expressway to provide
an additional lane and demolishing the bridge. The north rental car bus curb is not relocated. 
Cost Implications: $72,100,000 
Pros: 
(1)   Lower capital investment in the short-term 
(2)   Provides congestion relief 
(3)   Removes bridge and associated overload on Service Tunnel structure 
Cons: 
(1)   Additional improvements would be required to support Airport operations 
(2)   Requires  reconstruction  of  improvements; does  not  accommodate  future    road
realignment projects. 
(3)   Does not relocate the rental car bus curb to maximize the passenger load/unload space
in front of the terminal 
This is not the recommended alternative. 
Alternative 3  Widening of the southbound lanes of the Northern Airport Expressway to provide
an additional two lanes, demolishing the bridge, and relocating the rental car bus curb. 
Cost Implications: $79,300,000 
Pros: 
(1)   Provides congestion relief 
(2)   Minimizes reconstruction; accommodates future projects. 
(3)   Maximizes the passenger load/unload space in front of the terminal 
(4)   Removes bridge and associated overload on Service Tunnel structure 
Cons: 
(1)   Requires significant capital investment in the short-term 
This is the recommended alternative. 
FINANCIAL IMPLICATIONS 
Cost Estimate/Authorization Summary              Capital        Expense           Total 
COST ESTIMATE 
Original estimate                                $15,600,000               $0     $15,600,000 
Previous changes  net                         $33,900,000        $300,000     $34,200,000 
Current change                                $29,500,000              $0    $29,500,000 
Revised estimate                               $79,000,000              $0     $79,300,000 
Art (Transfer to Art CIP)                             ($200,000)                $0       ($200,000) 

Template revised June 27, 2019 (Diversity in Contracting).

COMMISSION AGENDA  Action Item No. 10b                                 Page 7 of 8 
Meeting Date: September 28, 2021 
Revised Total                                   $78,800,000        $300,000     $79,100,000 
AUTHORIZATION 
Previous authorizations                          $8,600,000               $0      $8,600,000 
Current request for authorization                $6,900,000               $0      $6,900,000 
Total authorizations, including this request      $15,500,000               $0     $15,500,000 
Remaining amount to be authorized           $63,300,000       $300,000    $63,600,000 
Annual Budget Status and Source of Funds 
This project (CIP #C800866) was included in the 2021-2025 capital budget and plan of finance
with a budget of $49,700,000. A budget increase of $29,300,000 was transferred from the
Aeronautical Allowance (CIP #C800753) for a total revised capital budget of $79,000,000. The
funding source for this project will be the Airport Development Fund (ADF) and future revenue
bonds. A total of $200,000 will be transferred to the Art Pool (CIP #C102066) pending this
request. The expense amount would be included in the annual operating expense budget. This
project will require Airline majority-in-interest approval. This project was included in the recent
ballot and results are anticipated by the end of September. 
Financial Analysis and Summary 
Project cost for analysis              $79,300,000 
Business Unit (BU)                  Roadways 
Effect on business performance     NOI after depreciation will increase 
(NOI after depreciation) 
IRR/NPV (if relevant)                N/A 
CPE Impact                       $.17 in 2026 
Future Revenues and Expenses (Total cost of ownership) 
This project will not have a significant impact on Aviation Maintenance annual operating and
maintenance (O&M) costs. Lighting will be a low maintenance LED system; the surface area of
asphalt will increase but otherwise the operating and maintenance costs would not significantly
change. The installation of ITS systems, additional signage, and landscaped areas are anticipated
to increase costs. 
ADDITIONAL BACKGROUND 
On June 8, 2021, the Commission was briefed on Ground Transportation. Several strategies were
identified to be further explored that would reduce environmental impact, reduce roadway
congestion, and advance transportation modes and programs to foster social equity and
customer choice. The Widen Arrivals Roadway project supports these efforts since it will provide
the basic roadway capacity and access necessary for private vehicles, commercial ground
transportation, and public transit services to access the Main Terminal and Garage. 

Template revised June 27, 2019 (Diversity in Contracting).

COMMISSION AGENDA  Action Item No. 10b                                 Page 8 of 8 
Meeting Date: September 28, 2021 
ATTACHMENTS TO THIS REQUEST 
(1)   Presentation slides 
PREVIOUS COMMISSION ACTIONS OR BRIEFINGS 
January 22, 2019  The Commission authorized design for $8,340,000 
















Template revised June 27, 2019 (Diversity in Contracting).