U.S. Department of Transportation
Federal Highway Administration
1200 New Jersey Avenue, SE
Washington, DC 20590
202-366-4000
The South Dakota Department of Transportation (SDDOT) was planning a project
to upgrade existing interchanges and build a new interchange on I-29 in Sioux
Falls, South Dakota. The interchange upgrades were planned on I-29 at the SD
42 interchange, which consisted of work on I-29 from Skunk Creek to the vicinity
of Russell Street and on SD 42 between Marion Rd and Lyons Boulevard. The new
interchange was being constructed at the intersection of I-29 and Madison Street.
When the project was in the preliminary design phase. Six people participated
in the audit: a representative from Road Design at SDDOT, a Pavement and Materials
Engineer from FHWA, the Sioux Falls City Traffic Engineer, the Sioux Falls Assistant
Public Works Director, a traffic engineering specialist from the DOT Local Government
Assistance, and the SDDOT
Region Traffic Engineer.
Team members reviewed preliminary project plans, crash data, traffic volume
data, and typical design manuals including: the AASHTO Road Design Manual, the
Federal Manual on Uniform Traffic Control Devices (MUTCD), the State of South
Dakota Standard Specifications, and the Highway Capacity Manual. Through the RSA , the report identified 35 safety concerns and findings ranging from access
management, to drainage improvements, to grading improvements, to modifying
construction phasing, to meeting ADA requirements. The safety benefits of some
recommendations were stated explicitly, such as in the discussion of snow removal
and snowmelt run off on the ramps. The report explained that lack of direct
sunlight could cause slick ramp conditions for extended periods of time. The
safety benefits of other improvements were implied as in the recommendation
to remove the proposed curb along the Interstate shoulders and ramps in the design.
The RSA report was six pages long.
