W. Quincy Ave. & S. Simms St.

Jefferson County, CO


MTJ  Roundabout Engineering was retained by Jefferson County to provide design mitigations to improve driver comprehension and reduce the number of crashes at the Quincy/Simms roundabout near Denver.


The MTJ design modification recommendations were predicated on:

  • Improving driver comprehension to mitigate driver errors
  • Matching capacity to demand to reduce conflict points
  • Simplifying drivers’ decision-making
  • Adhering to roundabout geometric safety principles
  • Best practices for roundabout signing and marking


  • Improved driver guidance
  • Reduced conflict points
  • Improved operations
  • Improved safety design
  • Simplified driver decision-making

MTJ also conducted a review of the nearby Simms/Nassau roundabout, and developed concept-level recommendations to ensure:  lane continuity between the roundabouts and the US-285 interchange ramp, simplified driver decision-making, and improved safety performance.

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