SC 46 & Bluffton Pkwy.

Bluffton, SC

MTJ Roundabout Engineering was retained by the FHWA Offices of Safety Peer-to-Peer program to provide assistance to the SCDOT, to review and provide low-cost modifications aimed at improving the existing roundabout’s poor safety record. Lane discipline crashes and failure to yield at entry were the predominant crash types.
MTJ developed pavement marking changes and assisted with field layout of these recommendations. The changes improved driver comprehension via positive driver guidance and optimal driver messaging to improve safety.



  • The solid-then-skip line type reduces driver recognition of correct lane use
  • Driver confusion due to multiple line types at entry
  • Misalignment from entry to circulating roadway – poor entry angles confusing priority message (who yields to whom)


MTJ Recommendations:

  • Provide a consistent circulating line type and entry marking modifications to improve driver comprehension for both circulating and entering driver messaging
  • Realign circulating lane line to improve entry alignment and view angles
  • Modify/remove markings at entry area to clarify,
    including a stronger Yield Line
    (dotted edge line extended)


Result: Post-modifications crash data show an 80% reduction in crashes.


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