In the early days of motor vehicle travel, an urban area’s transportation infrastructure consisted mostly of two-lane roads. This provided sufficient traffic flow for the relatively small number of vehicles. But over the years, vehicle ownership rates rose and traffic congestion increased. Our roads needed to be updated to support this increasing traffic.
In the 1950s and 1960s, the problem of higher traffic volume was solved by increasing the number of lanes on the roads, from two to four. There were no engineering groups exploring other options or considering whether four-lane roads were the best solution in all cases.¹ Four-lane roads became the norm for urban areas throughout the country.
As a result, our roads got bloated.
In the years since, we’ve gained a better understanding of the challenges that four-lane roads present to road safety, including:
To counteract the dangers posed by four-lane roads, the Federal Highway Administration (FHWA) is now recommending that we put our roads on a diet.
The term “road diet” generally means removing lanes from a road and using that space for other purposes. Typically, this road rechannelization involves turning an undivided four-lane road into a three-lane road with two through lanes and a center two-way left-turn lane.² The safety benefits of this relatively easy, cost-effective countermeasure can be significant. In fact, studies suggest that a road diet converting a road from four lanes to three can reduce total crashes 19-47%³ and can reduce crashes involving both drivers under 35 years old and those over 65 years old.⁴
Here are just a few of the safety benefits of a lane reduction from four lanes to three:
To ensure that your road diet is successful, it’s important to choose the right pavement markings to help drivers interpret and react to the road. And in challenging conditions like nighttime or rain, not just any markings will do.
Here are a few key characteristics of effective pavement markings:
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⁴ Source: Stout, Thomas B., Before and After Study of Some Impacts of 4-Lane to 3-Lane Roadway Conversions. March 2005.
⁵ Source: SBD Automotive — ADAS Tracker — AUT 534. June 2016.
⁶ Source: Predicted availability and fitment of safety features on registered vehicles. (2017). Institute, Highway Loss Data. Vol. 34. No 28, September 2017.
Get information about road markings that are easy to apply, provide all-weather visibility and will help you plan and execute a successful road diet?
Check out our 3M Pavement Markings