Another modern solution to traffic, transportation, and infrastructure design problems is convertible roadways and lanes. This technique refers to roadway facilities that modify the existing geometry to temporarily increase capacity for high congestion situations.
In cities like Washington, DC, major highway systems utilize convertible roadways and lanes to flow traffic in one direction during peak hours, special events, or emergency situations. For example, a roadway consisting of six lanes (three in both directions) can be converted to have only two lanes operational in one direction while the other four lanes move in the opposing direction to boost capacity for a short duration. In the Gulf South and Eastern states, residents are familiar with this technique in hurricane evacuation scenarios which often involve all major highway systems moving in only one direction, out of the area of the hurricane’s path.
Convertible roadways and lanes can be a cost effective alternative to adding lanes to manage highly congested areas. They provide flexibility, encompassing a variety of techniques that afford an agency with options for how and when it responds to the needs for more on-street parking, additional intersection turning capability, and short-term corridor capacity.
Read ABMB Traffic Division Manager Laurence Lambert's published study NCHRP Convertible Lanes and Roadways: A Synthesis of Highway Practice.