Bigger and wider does not always mean safer

For the last half century, we have designed roads in America with the intention of preventing crashes and mitigating their effects when they do happen. Unfortunately, this design also invites one of the leading causes of roadway accidents: speed.

There is an old axiom stating that “speed kills, ” which is especially true in towns and highly urbanized areas. Yet most roadway designers around the world turn to the "Forgiving Highway" rather than slower speeds as the way to ensure safety. The "Forgiving Highway" includes features such as breakaway supports, burying the end of guardrails, clearing the roadside of unneeded obstacles, and flattening and rounding slopes and ditches. In other words, to make our roads safer, we clear our roadside of “fixed objects” such as trees, light poles and other objects, as well as create clear zones to bring vehicles to a controlled stop if and when they leave the road. While this helps motorists when they do leave the roads, there is an unintended consequence:

Speeds of all vehicles increase because motorists set their pace in response to the environment of the roadway. When they are put on a stretch of road that is wider, flatter, and straighter, they will naturally drive faster.

These higher speeds may be okay on freeways where there are no adjacent homes, businesses or pedestrians and where sight distances are near infinite, curves are flat, and opposing roadways are separated by wide medians or center barriers. But it is definitely not a safe condition where these conditions do not exist. In the United States, we were so caught up in the paradigm that we were doing the right thing to increase safety that we never stopped to check if we were getting the desired result—safer streets.

Even today, groups with credible sounding names such as the National Transportation Coalition, whose membership is made up primarily of highway contractors, continue to advocate for bigger roads. But more and more people—from transportation experts to road users themselves, are questioning whether wider and bigger roads make sense. This shift is reflected both inside and outside the transportation industry through the context sensitive solutions movement, which advocates for road design that respects community and natural environments and is guided by a shared stakeholder vision.

Luckily, there are also many great examples of streets around the world that safely and successfully manage multiple users and modes, in both small towns and big cities. To read about and see images of these great streets around the world, visit the Great Public Spaces section of our website.