Roundabout Guides

Three things that make roundabouts green  3. Reduce Noise Pollution 2. Reduce Greenhouse Gas (GHG) Emissions  1. Reduce Types of Crashes that most often lead to fatalities*  *Ok, so No. 1 is less about being green and more about saving lives.

The City of Columbia currently has 29 roundabouts, Boone County maintains one and the Missouri Department of Transportation operates an additional 10 roundabouts along U.S. Route 63 and Interstate 70.  Roundabouts reduce serious injury and fatality crashes by up to 80% while maintaining or improving traffic flow.  Here are six tips on successfully navigating a roundabout:  1. Slow down as you approach the roundabout, and be prepared to stop for pedestrians.  2. As you approach the roundabout, watch for signs and lane markings to help you select which lane you need to be in.  3. Before you can enter the roundabout, you will see a yield sign. Street Talk: Tips on using roundabouts This means you must stop only if there is already traffic in the roundabout. Simply wait for the traffic to pass, and then enter. If the way is clear as you approach the roundabout, then you may enter the roundabout without stopping.  4. Once inside the roundabout, changing lanes is discouraged.  5. Use your blinker as you approach the exit you intend to use.  6. Since vehicles are moving more slowly, roundabouts can provide a better cushion for errors. However, you should always try to avoid a collision and do what you must to avoid one if necessary. Generally, you should not stop when you are inside the roundabout to let other drivers in, but also do not accelerate to try to block incoming traffic.opens PDF file

Roundabout Diagram















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Roundabouts are a proven means of controlling traffic at intersections, discouraging speeding, reducing emissions and lowering the rate of fatal crashes. Approaching vehicles must yield to pedestrians in the crosswalk and to traffic in the roundabout. When you enter, yield to circulating traffic from the left, but do not stop if it is clear.











Slow down: Reduce your speed and prepare to stop if there is traffic in the roundabout. - Yield: Do not proceed beyond the yield sign until all cross traffic is clear. - No merging alongside other cars: Entering drivers are not permitted to merge alongside traffic already in the roundabout, even if there is more than one lane. - Find a gap: Enter the roundabout when there is a safe gap in all lanes. - Go right: Cars always enter right and exit right. 10 TIPS FOR ROUNDABOUT DRIVING - Stay in your lane: You should choose the correct lane before entering the roundabout and stay in that lane. - Be doubly careful in double roundabouts: Traffic may sometimes cross in front of you after you have entered the roundabout, so be ready to yield. - Right of way is not always right: Aggressively asserting your right of way with your accelerator isn’t prudent. Once you’ve safely entered, you have the right of way, but this doesn’t give you the right to hit someone. - Drive cautiously and politely: Always be aware that other vehicles may not understand how the roundabout works. Patience and courtesy brightens everyone’s day and keeps traffic moving. - Learn as much as you can: Links to instructional videos and other information about driving in single-lane roundabouts is available at PDF file

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