Roundabouts are a great way to enhance public space, beautify a street, and create iconic gateways. We've established that roundabout are also safer.
A traditional intersection has 32 potential vehicle conflicts and 24 pedestrian–vehicle ones. In contrast, a roundabout has only 8 potential vehicle conflicts and 8 pedestrian–vehicle ones. Collisions on a roundabout are also more likely to be minor fender benders than dangerous and costly T-bone collisions. Overall, the Federal Highway Administration has found roundabouts reduce injury crashes by 75 percent and fatal crashes by a whopping 90 percent. Because roundabouts slow vehicle traffic down considerably, any collision with a pedestrian is less likely to be fatal.
We also know--especially in light of our two new roundabouts at West Blvd.--that they improve the driving experience. Traffic flows better when you don’t make cars wait for a light to change. Stop-and-go traffic can be frustrating, and all too often, rushed drivers try to avoid red lights by cutting through parking lots, which is also dangerous for unsuspecting pedestrians and drivers. Because roundabouts keep traffic moving, its common to see at least a 20% reduction in delays — and safer parking lots too. Traffic flows better but drivers also slow down considerably, allowing them to really see the businesses along the street.
Did you know that roundabouts also create economic vitality and enhance the businesses on the street? A street similar to the Business Loop in Golden, Colorado replaced 4 traditional intersections with roundabouts and here are the results:
Easier Access to Businesses: Pre-installation, businesses relied on left-turns with an average delay at business access points of 28 seconds, and a maximum delay of 118 seconds. Post-installation, right in/right out access was created and the average delay into businesses was reduced to 13 seconds with a maximum delay of 40 seconds.
Economic Impact: Sales tax revenues along the corridor, increased 60% in the six years post-installation. South Golden become the only area in the city reporting continued growth in sales tax revenues in the face of a metro-wide economic slowdown. In addition, over 75,000 square feet of retail/office space has been built in the corridor since the installation of the roundabouts.
Accidents Decreased: Total annual accidents dropped from a pre-installation high of 123 accidents per year to only 19. Injuries also dropped from 31 injuries in the 3 years pre-installation to only 1 in the 4 years after installation.
Slower Speeds: Post-installation, speeds declined from 47 mph to 33 mph (as measured by top speeds between the roundabouts.)
Faster Travel Time: Prior to the roundabouts, the section of corridor had 2 traffic signals and average travel time through the corridor (with green lights) was calculated to be 78 seconds. A third traffic signal was being considered which would have increased travel time to 103 seconds. Post installation travel time through the corridor dropped to 68 seconds.
Time and again, it's been found that roundabouts--especially when part of an overall corridor improvement plan--help established businesses thrive and encourage new businesses to locate there.
Read about the positive economic impact of roundabouts and about how roundabouts improve access to businesses.