• Reduce the number and severity of collisions
• Curved lanes and one-way travel minimize high-speed T-bone and head-on crashes
• Lower vehicle speeds, typically 15-20 mph, provide more reaction time, so if a collision does occur, it tends to be minor
• There are fewer potential conflict points.
  • A single-lane roundabout has eight vehicle and eight pedestrian conflict points, compared to 32 vehicle and 24 pedestrian conflict points at a comparable signalized intersection.
  • Multi-lane roundabouts would have additional conflict points, but still offer fewer conflict points than comparable signalized intersections

Roundabout vehicle and pedestrian conflict points	Signalized intersection vehicle and pedestrian conflict points
Image Source:AARP

• Continuous traffic flow with less delay
• Less idling and stopping/starting means less fuel consumption.
• Fewer stops mean smoother trips for all users

• Though generally similar to initial construction costs, there are no ongoing signal maintenance and electrical costs

• Roundabout designs set crosswalks back from the vehicle intersection, simplifying the driver and pedestrian task by allowing drivers and pedestrians to focus on one conflict point and one direction at a time. 
• Pedestrian-activated signals like Rectangular Rapid Flash Beacons (RRFBs) increase crosswalk visibility. Bright flashing lights indicate a pedestrian's presence. These safety measures are visible day and night, ensuring the safety of pedestrians and cyclists at all times.

Image illustrates how crosswalks are set back from the roundabout lanes. Rectangular Rapid Flashing Beacons indicate the presence of a pedestrian and are visible both day and night. Image Source: Google Maps

When approaching a roundabout, drivers should slow down to a speed between 15 and 25 miles per hour. It is important to yield to all traffic circulating within the roundabout before entering. Once inside, drivers should continue moving without stopping. Large vehicles such as buses or trucks may require additional space and could use both lanes or the central apron to complete their turns—drivers should avoid attempting to pass them. As you prepare to exit the roundabout, use your turn signal to indicate your intended direction and provide clarity to other road users.

Bicyclists have two options when navigating a roundabout. They may ride through the roundabout in the same manner as motor vehicles, following the same rules of yielding and signaling. Alternatively, cyclists may opt to dismount and use sidewalks or designated crosswalks, in which case they should follow the same rules and signals as pedestrians.

Pedestrians should use the marked crosswalks located before the roundabout's entrances and exits. Before crossing, looking for approaching vehicles and making eye contact with drivers is essential to ensure visibility. Where available, pedestrians are encouraged to use Rectangular Rapid Flash Beacons (RRFBs) to increase driver awareness and enhance safety while crossing. 

 Modern roundabouts are not the same as older-style rotary traffic circles. Unlike the large, high-speed, and often confusing traffic circles of the past, today's roundabouts are smaller in scale, designed to promote slower vehicle speeds and provide clear lane guidance. In modern roundabouts, vehicles enter curved lanes and must yield to vehicles already in the roundabout, with well-defined lanes that enhance driver understanding and control. Additionally, pedestrian walkways are strategically placed before cars enter the roundabout, ensuring increased safety for all individuals using the intersection, whether by car, on foot or by bike. Today's roundabouts are smaller, more intuitive, and much safer for all users.

Earlier rotary traffic circles were generally designed for higher speeds, encompassed a much larger footprint and might include stop signs or traffic signals for various through movements.
Some had multiple lanes entering and exiting with no clear lanes identified within the circle creating somewhat of a “free for all” movement.
	Photos courtesy of Google

Roundabouts support Shoreline’s goals of improving safety, reducing emissions, and enhancing transportation efficiency across the city.