We already knew roundabouts, used widely in Europe and other locales, were better for fuel efficiency and safety, but according to a recent mythbusters episode, they are more efficient for motorists, too. By about 20%. In our 2011 Lakeview Area Master Plan, we proposed a traffic bean with pedestrian islands to improve traffic flow and make street crossing easier and safer for pedestrians and cyclists, and now we know that there is nothing to lose in terms of speed.
A roundabout eliminates merging, which is a task that requires a lot of high attention from all motorists. We’re not saying people that are driving shouldn’t always be paying a lot of attention—but merging requires the participation of everyone at the wheel, and to estimate movements based on perceived speeds, which can be tricky. Not to mention that it’s a hotbed of risk for cyclists riding with the flow of traffic. In a nutshell, as this diagram demonstrates, roundabouts have about 8 points of vehicular conflict and 8 points of pedestrian conflict; a standard four way intersection has 32 points of vehicular conflict and 24 points of pedestrian conflict.
Mythbusters also linked to a series of nine videos that explain how roundabouts work, helpful for dispelling some of their mystique! Take a look at our renderings below of the roundabout traffic bean we envisioned for the LAB intersection (Lincoln, Ashland, Belmont)—that behemoth of a six way intersection that takes forever to cross as a pedestrian and is intimidating as a driver too! Phase 1 (see below) of our LAB improvement would include new crosswalks and pedestrian islands, and Phase 2 (opening image) would include the remodeling of bus stops, a sidewalk extension, and the addition of a plaza to make the area more hospitable to pedestrians. Watch the video for the complete plan overview here.