3.0 Affected Environment - Knik Arm Bridge and Toll Authority

Knik Arm Crossing DraftFinal EIS
Affected Environment
Seward Highway
The Ingra-Gambell/Seward Highway corridor, operated by ADOT&PF, is a major northsouth
route, on the NHS and serves the Anchorage Bowl as a continuous north-south
connection down the center of the urbanized area of Anchorage. At its northern end, the
corridor consists of the Ingra-Gambell Couplet. Between 3rd Avenue and Midtown, the
corridor operates as a controlled access highway. Traffic volumes are very high. Average
daily traffic on the Seward Highway has been recorded at 54,000 in Midtown
(ADOT&PF 2004a). Most crashes on the Seward Highway take place in at-grade
intersections and on the ramps of interchanges between Fireweed Lane and DeArmoun Road.
The Seward Highway is on the “Top 50 Locations” list from 1997 through 2004
(MOA 2004c). The majority of crashes occur in the urban section between Fireweed Lane
and 36th Avenue.
A-C Couplet/Port Access Road
A and C Streets form a couplet that functions as a major arterial running north-south from the
southern edge of Government Hill, through Downtown Anchorage and Midtown. The
couplet becomes a single roadway (C Street) south of Midtown. A Street is the northbound
roadway and C Street is the southbound roadway. Both A and C Streets are three-lane roads
south of 3rd Avenue. North of 3rd Avenue, A and C Streets join to become a two-way, fourlane
facility that crosses Ship Creek on a viaduct. The A-C Viaduct connects to Loop and
Ocean Dock Roads at the north end and is commonly referred to as the Port Access Road.
Most vehicles and trucks originating at or bound for the POA or Government Hill/Elmendorf
area use this access route. Vehicles bound for Ship Creek businesses, the Alaska Railroad, or
Ship Creek Point use either the A-C Viaduct/Port Access Road or E Street. ADT has been
reported at 16,600 on the A-C Viaduct and 28,000 between 5th and 6th Streets (16,600 on
C Street and 11,400 on A Street) (ADOT&PF 2004a). A and C Streets are constructed to
accommodate four lanes in each direction. C Street between 5th and 6th Avenues has been
consistently on the “Top 50 Locations” list from 1997 through 2004. The highest number of
crashes, 46, occurred at the intersection of C Street and 6th Avenue in 2004 (MOA 2004c).
The configuration of the intersection was changed in 2003 at the time of the construction of
the National Parks building. In 2005, the intersection of C Street at 6th Avenue was
improved. Parking was removed along with the dual left turns, and the parking lane became a
left turn lane. A and C Streets are constructed to eventually accommodate four lanes in each
direction. The 2005 Anchorage LRTP mentions an expansion to four lanes to accommodate
expected growth in traffic demand (MOA 2005a). A-C Streets are operated and maintained
by the ADOT&PF and are part of the NHS.
Ingra and Gambell Streets
Ingra and Gambell Streets are one-way major arterials running north (Ingra)-south (Gambell)
from 3rd Avenue to the Seward Highway. They function in a manner similar to A and
C Streets. Both Ingra and Gambell Streets are three-lane roads connecting Seward Highway
to the eastern edge of Downtown Anchorage. They join south of 15th Avenue and become
Seward Highway. Ingra and Gambell Streets at the intersections of 5th and 6th Avenues were
consistently on the “Top 50 Locations” list between 1997 and 2004 (MOA 2004c).
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