DSM Terminal-Area-Concept-Plan-Technical-Report - FINAL

Ground Transportation Facilities and Conditions
Roadways
KEY POINTS
• Terminal access is via
Cowles Drive
• Access to Cowles drive is
primarily via Fleur Drive
and secondary access is
via Duck Pond Road
• The existing roadways
do not have capacity
constraints, however,
there are a variety of
operational and safety
concerns:
— Two Lane Roads
— Intersections
— Decision Distances
— Two-Way Decision
Points
— Channelization
— Prioritized Access
Route
The roadway network for the terminal complex is shown in Figure 9. The
passenger terminal is accessed via a roadway loop, Cowles Drive, accessed
primarily via Fleur Drive, a major north-south arterial. There are two
entrances , a channelized right turn and an un-signalized left turn off Fleur
Drive. The Airport exit intersection with Fleur Drive is signalized.
Secondary access to Cowles Drive is provided via Duck Pond Road, which
parallels Fleur Drive from McKinley Drive on the north to Army Post Road
on the South. To the South, the road becomes South Frontage road, wraps
around the Runway 31 threshold, and provides access to Economy Lot #4
and the Rental Car QTA. On the north side, the road wraps around the
Runway 23 threshold and provides access to the general aviation complex.
Cowles Drive does not have any capacity constraints. However, several
airport roadway planning, operational, and safety considerations are
discussed below. These issues are also identified in Figure 9.
Maintain two lanes on inbound/outbound roadways – Primary access
roadways should be at least two-lanes wide to avoid a single point of
failure due to a traffic incident or similar event.
Avoid intersections in final vehicular approach and exit – Drivers at
airports are often unfamiliar with the roadways and can be distracted.
Intersections on the Airport’s primary access road become safety hazards
and congestion points. Cowles Drive has two intersections.
Provide appropriate distances between ‘decision points’ – Airports should
be particularly careful to provide appropriate distances between decision
points. Short decision distances become safety hazards and congestion
points. At three locations within the Cowles Drive loop, decision distances
are sub-standard.
Decision points should be limited to two options/routes – Decision points
should be limited to two-way decisions, where drivers only choose
between two options/routes. After the curbsides on Cowles Drive, there is
a four-way decision point between two rental car lots, Economy Lot #3,
and the main exit route.
Create well defined channelization from toll booths and merges – At toll
plazas and merging lanes there should be a well defined channelization.
The existing public parking exit plaza has six lanes simultaneously merging
into a single lane at Cowles Drive.
Prioritize access route – Airport entrances should have prioritized access.
The northbound entrance to the Airport does not have a signal; entering
traffic must continually yield to southbound traffic on the busy Fleur Drive.
Figure 9
Airport Roadway Operational Issues
Des Moines International Airport
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TERMINAL AREA CONCEPT PLAN TECHNICAL REPORT
Des Moines International Airport