LQC is an interesting method. It is very effective for considering closing or narrowing streets. You can see how traffic accomodates to a temporary closing or narrowing before making the capital expense of permanently reconstructing the street.
"LQC or “Lighter Quicker Cheaper.” LQC is a strategy coined by Eric Reynolds of the planning firm Urban Systems Management. LQC defines a method for rolling out fast, simple, and low-cost solutions in the built environment which will organically spawn permanent and more meaningful development. By planning and implementing a minimally viable, simple solution to public space, the stage is set for future evolutions of space that will be infinitely more complex and enjoyable. Managing the ability to create effective solutions in balance with bureaucratic stop-gaps and long time frames have been found in temporary, simple innovations which provide solutions that can quickly pass through bureaucratic channels with minimum levels of perceived risk."
"In 2009, the Department of Transportation, along with the Times Square Alliance closed several lanes of traffic ‘temporarily’ in the middle of Times Square. Following closure, a thin layer of paint and texture was applied to these areas where removable tables and chairs were placed. The concept was described to NYC public agencies and the public as a reversible “experiment.” Consequently, the space was widely lauded and used, and eventually made permanent by the Bloomberg administration. If Sadik Khan h ad introduced this idea through the more traditional channels of a massive capital improvement project which would permanently alter a major arterial thoroughfare in Times Square, the changes may not have taken place."