Did you know?

types of crashes lead to traffic fatalities

56% of crash fatalities nationally were frontal collisions,

24% were right angle collisions,

6% were rear end collisions and

14% were other types of crashes (single vehicle/rollovers/etc.).

Source: Insurance Institute for Highway Safety (IIHS.org)



Roundabouts are not a cure-all.

Whether a crash leads to a fatality in a given case depends on human factors that can’t be controlled by engineering design alone, including the use of seat belts, impaired driving, type/size of vehicles involved, distracted driving, age/health of vehicle occupants, etc.

What roundabouts excel at is:

minimizing 
the types of crashes
that occur at an intersection

 

Frontal collisions (head-on, left-turn)

are practically eliminated.

 

Right-angle collisions

are greatly reduced and occur at lower speeds
with less severe angles.

 

Rear-end collisions

are reduced and occur at lower speeds.

 

Low speed merging/swiping collisions

may or may not increase slightly (taking the place of the more severe types of crashes), but the angle of impact leads to fewer serious injuries compared to frontal, right-angle and rear-end crashes.


In addition to improving safety, roundabouts also:

Improve traffic flow

For example, studies by Kansas State and the Insurance Institute have found a 20% to 89% reduction in delays at roundabouts.

 

Simplify complex intersections

For example, when multiple roadways of different capacity merge, or when streets merge at unusual angles due to geography or existing infrastructure. 

 

Require no electricity

During power outages, the roundabout functions normally compared to signalized intersections.

 

Reduce noise

Less acceleration and braking reduces noise pollution.

 

Save fuel

Better fuel efficiency and reduced greenhouse emissions also results
from less acceleration and braking.


    Educational Pages:

    Forum & Green Meadows Roundabout

    Safety Tips

    Conflict Points


    Video Tutorials:

    USDOT: Modern Roundabouts: A Safer Choice (Video)

    Roundabout How: Yield, Enter and Exit (Video)

    MoDOT: All About a Roundabout (Video)

    IIHS: How Roundabouts Work (Video)

    Mini Roundabouts (Video)


    Resources:

    Interactive Columbia Roundabout Map 

    U.S. Department of Transportation/Federal Highway Administration: Safety.fhwa.dot.gov/intersection/innovative/roundabouts

    Washington State Department of Transportation: Wsdot.wa.gov/Safety/roundabouts

    Insurance Institute for Highway Safety: iihs.org/topics/fatality-statistics/detail/yearly-snapshot

    Public Involvement Process

    Columbia Public Works Engineering



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