UPD A T E what is today the neighborhood of Mountain View (which had a 1950 population of 2,880). The Seward Highway remains a two-lane highway south of Anchorage, the only road from Anchorage to Girdwood, Whittier, and the Kenai Peninsula. Inside urban Anchor- age, the original two-lane highway is known is the Old Seward Highway and parallels the
path of the current highway.
Construction of the four-lane New Seward
Highway was completed in 1971, with a series
of interchange expansions occurring over the
next two decades. The current highway between south and midtown Anchorage is a modern “controlled access” freeway, which means
drivers can only get on and leave it at a limited
number of designated entrances and exits.
According to a 2016 traffic study, the Seward
Highway had busier sections of highway than
any other road in Alaska except for the Glenn
Highway. The busiest section of the Seward
Highway was in midtown just north of 36th
Avenue, where average daily traffic was 56,990
vehicles a day. The next busiest section was between Dowling Road and Dimond Boulevard,
where traffic averaged 56,837 vehicles per day.
For reference, Anchorage’s total population in
2016 was just less than 300,000 people. The busiest highway section of the state, on the Glenn
Highway, averaged 65,172 vehicles per day to
the east of the Muldoon Road intersection.
A Decade of Planning
Planning to make the Seward Highway a six-lane highway began more than a decade ago
with public meetings and an environmental
assessment that was written between 2001
The project has three main goals, says
Project Manager Sean Baski, PE, with the
Alaska Department of Transportation: to
improve safety, to improve congestion, and
to improve cross corridor connectivity, the
flow of traffic on the east-west streets around
The project adds two main highway bridges that will allow traffic to pass below. One is
located where 76th Avenue meets Lore Road
on the section of highway under construction this year. Another is where the newly-renamed Scooter Drive will meet Academy
Drive under a yet-to-be-built highway bridge.
The Scooter/Academy Drive intersection is
part of the final third of the project.
The 2007 environmental document for
the Seward Highway project covers a large
section of highway from 36th Avenue on
the north end to Rabbit Creek Road to the
south. But the Department of Transportation
focused on the middle section, from Tudor
Road south to O’Malley Road.
For the southern end of the corridor, the
project planners decided the highway didn’t
have enough traffic between Rabbit Creek
and O’Malley Road to merit widening from
four lanes to six.
The northern end of the corridor was
wrapped into a different road improvement
project called the Midtown Congestion Relief
project, which extends north to 20th Avenue.
North of Tudor Road, the Seward Highway
Introducing the ‘Diverging Diamond’
transitions from a freeway to a busy arterial
city street. This part of the highway is actual-
ly the busiest section. According to the proj-
ect website (http://midtowncongestionrelief.
com), the midtown part of the corridor also
has a “long history of unfinished projects
that similarly sought to address traffic con-
gestion issues.” Work on the midtown part of
the Seward Highway is in a pre-design phase.
The next step is a PEL, or planning and envi-
ronmental linkages, study. An open house to
discuss the project was held in January.
and a Street Named for a Cat
The new Seward Highway expansion plans
call for a style of interchange that’s relatively
new to Alaska, the “diverging diamond.” In
this style of interchange, drivers make a figure eight type path, temporarily switching
to the left of the oncoming lane as they cross
over or under a highway bridge.
The advantage of this intersection style is
that it’s easier to make easier left turns onto the
highway, because it doesn’t require crossing
oncoming traffic. Additionally, it’s a relatively
inexpensive interchange that can be built with
budget similar to traditional diamond-shaped
interchanges and in about the same space.
The first diverging diamond interchange
in the United States was built in Springfield,
Missouri in 2009. Alaska’s first diverging
diamond recently went up where Muldoon
Road passes over the Glenn Highway, and
drivers have been figuring it out, Baski says.
“The word is things are going well,” he
says. “As with any interchange, there are
things to learn about it. The thing about diverging diamonds is they’re pretty intuitive.
Even though you’re crossing to the other side
of the highway, some people don’t even notice
they’re doing anything different. You get in
the left lane if you want to turn left, you get in
the right lane if you want to turn right.”
The next section of the Seward Highway
project calls for diverging diamonds where
the highway crosses over Dimond Boule-vard/Abbott Road and where it crosses over
The new highway will also feature a new
raised section that will allow traffic to pass
underneath. South of Dimond Boulevard
and north of O’Malley Road is Academy
Drive, a street that dead-ends at a Seward
Highway access road.
In this section, the Seward Highway separates Independence Park, a large neighborhood, from the Dimond Center shopping
mall. There’s not currently a convenient way
to cross the highway at this location, but pedestrians found a way despite fences intended to discourage them.
“There are a lot of youth who cross the highway. The state has fences along this stretch
and for a long time youth have gone out and
clipped all of the fences on that stretch and our
maintenance crews have gone out and fixed it,”
Baski says. “There’s an obvious need for cross-
corridor connectivity on the pedestrian front,
getting across the highway. The main attrac-
tant is obviously Dimond Center mall.”
When the highway project is complete,
both pedestrians and drivers will be able to
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