COMMISSION 
AGENDA MEMORANDUM                        Item No.          9a 
BRIEFING ITEM                            Date of Meeting       April 10, 2018 
DATE:     April 2, 2018 
TO:        Executive Director Stephen P. Metruck 
FROM:    Michael Ehl, Director Aviation Operations 
Jeffrey Hoevet, Senior Manager Airport Operations 
SUBJECT:  Airport Drives Traffic Enhancement Briefing 
EXECUTIVE SUMMARY 
Sea-Tac's roadway system was designed in the late 1960s when the Airport facilitated the
movement of 5 million annual guests.  Replacement of the original return-to-terminal loops,
immediately adjacent the parking garage, with the South 160th Street recirculation loop in
2008 assisted in removing some 40% of recirculating traffic from the inner drives, and
effectively expanding the projected practical capacity of the system beyond its saturation at 40
million annual guests which was forecast in 2016-2017. 
Given Sea-Tac's record 40 percent growth in passengers between 2012 and 2017, the roadway
system is again strained in peak operating periods, regularly resulting in stop and go conditions
on the inbound/southbound lanes of the Northern Airport Expressway. While these conditions
historically affected Arrivals/Lower Drive traffic and were limited to nighttime holiday peak
periods, 2017 saw the emergence of impacts spread more broadly across the operating day, to
include daytime impacts to the Departures/Upper drives. 
Equally dynamic in nature has been the changing mode split for ground transportation options
available to Airport patrons.   In particular, the introduction of Transportation Network
Companies (TNCs) to Sea-Tac in 2016 drastically altered the volume of vehicles using the
roadway system as necessitated by the transit from remote holding lots to the customer pickup
area on the third floor of the parking garage. 
Recognizing that completion of roadway capital improvements to address the long-term
capacity needs of the Airport is currently slated for 2020-2021, this briefing is intended to
inform the Commission of near-term operational mitigations which are currently underway to
provide improvement in the summer of 2018 and beyond. 
ADDITIONAL BACKGROUND 
During the holiday season of 2012, Aviation Division staff and the Port of Seattle Police
Department implemented the Traffic Mitigation Plan (TMP) initiative to mitigate anticipated

Template revised September 22, 2016.

COMMISSION AGENDA  Briefing Item No. 9a                                  Page 2 of 3 
Meeting Date: April 10, 2018 
high traffic volumes. Specifically, this plan restricts access to the southbound Airport freeways
by closing the Air Cargo Road on-ramp, thus preventing large numbers of taxis, TNCs, and
smaller number of other GT vehicles from impacting the traffic flos as they merge and weave
across three lanes of traffic to enter the third floor plaza of the parking garage.  The TMP has
been implemented approximately 12 times since November 1, 2017. 
While the TMP has been very effective over the ensuing 5 years in rapidly counteracting long
queues of traffic entering the Airport drives system during peak periods, it is a reactive measure
which is labor intensive and less than ideal in its impact on customers and GT operators alike.
As such, Aviation staff is pursuing other modifications that are proactive and considerate of
other objectives.  The first modification identified for implementation is the use of TNC Re-
Match procedures. 
In November 2017, the Port worked with the TNCs to implement a trial of new rideshare
application feature, utilized at many airports across the country, known as Re-Match. The
feature allows for TNC drivers who have just completed a passenger drop-off on the Airport's
departure drive to receive an immediate dispatch for a passenger pick-up in the ground
transportation plaza in the garage. The benefit to the driver is that they do not need to travel
back to the 160th Street holding lot and wait for a passenger pick-up dispatch from their TNC.
Instead, the driver exits the departure drive and utilizes the return to terminal loop and enters
the garage pick-up area to receive their passenger. 
The TNC's main interest in implementing Re-Match is to reduce the waiting time for passengers
requesting a pick-up from the Airport, which, of course, is a goal of Port staff as well. During the
duration of the pilot of Re-Match, passenger wait times have been reduced by a third,
according to information provided by the TNCs. 
TNCs are very enthusiastic about the power of Re-Match to reduce deadheading trips to the
airport, while also expanding opportunities to those drivers who have previously not been
permitted to pick up passengers. TNCs' environmental performance is measured via the E-KPI,
which uses vehicle fuel efficiency, deadhead reduction, and ridesharing factors to determine if
TNCs are meeting the environmental equivalent of the taxis' contracted 45 MPG and 93%
deadheading rate (set while Puget Sound Dispatch/Yellow Cab was still under contract). 
When the TNC pilot was first launched, TNCs were unsure how to meet the E-KPI and decided
to focus on restricting pickup events to only those drivers possessing high fuel efficiency
vehicles, rather than on deadhead reduction or increasing ridesharing. Thus, many TNC drivers
who dropped passengers at the airport were unable to pick up due to the restriction imposed
by the TNCs. However, during the Re-Match pilot,  the TNCs relaxed the fuel efficiency
restriction only for those vehicles that had provided a drop off, as a means of reducing the
amount of deadheading occurring to serve airport passengers.  The results have slightly
lowered the average fuel economy of pickup events while dramatically reducing deadheading. 
We estimate roughly 30,000 deadheading trips to the airport were avoided during the month of

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COMMISSION AGENDA  Briefing Item No. 9a                                  Page 3 of 3 
Meeting Date: April 10, 2018 
December.  The participating TNCs E-KPI performance increased during the pilot while also
expanding opportunity for drivers, and reducing vehicle miles traveled by TNC operators. 
The Port has realized other important benefits from Re-Match as well, including: 
(1) Significant reduction in congestion and traffic within and around the 160th  Street
holding lot. 
(2) Improvement in Airport expressway congestion close to the terminal as fewer TNC
drivers merge onto the Airport expressway from the Air Cargo Road/South 170th Street
on-ramp; this benefits all Airport expressway users, including private citizens as well as
other modes of commercial transportation including taxis, limos, shuttles, etc. 
As part of the Re-Match trial, the Port and TNCs have worked closely to find additional
improvements that could be implemented to further improve the efficacy of Re-Match. One
such revision is to utilize a ramp from the departure drive back to the south entrance of the
Airport garage for TNC Re-Match vehicles. By allowing this routing into the garage, TNC Re-
Match drivers would be able to avoid utilizing the return to terminal loop to enter the garage
for their passenger pick-up. With this change, two significant benefits would be realized: 
(1) Passenger wait times would be further reduced, as drivers would have significantly less
distance to travel to get to the TNC pick-up area within the garage. 
(2) Airport expressway congestion would see additional improvement as the TNC Re-Match
vehicles would avoid the return to terminal loop to enter the garage. 
Port staff is currently developing the implementation strategy for the south entry and working
with  both  the  TNC  partners  and  internal  Port  stakeholders  (including  Environmental,
Operations, Parking, etc.) in finalizing the optimal layout and policies for the program. Staff's
goal is to implement the garage south entry program in early April. 
ATTACHMENTS TO THIS BRIEFING 
Presentation slides 
PREVIOUS COMMISSION ACTIONS OR BRIEFINGS 
None 





Template revised September 22, 2016.