Project Abstract

There are many reasons that substantiate the need to perform a detailed study of pedestrians for the proposed WTC Memorial site. Because of the complex pedestrian environment created at the site, the ability to readily evaluate pedestrians would be difficult. The most effective way to analyze the site would be to “scale” in two-dimensions in real time. As part of this study, an accurate depiction of not only pedestrian movements on the site but pedestrian behavior is needed to fully understand how the site is used by pedestrians and how efficiently the site operates. Typically, pedestrians are not included as part of the design process as “rule-of-thumb” and general standards are used in lieu of empirical data. The main question the detailed analysis would answer is whether the design could adequately accommodate the projected number of persons that would visit the site, without detracting from the design intent. The full benefit of the software would not be realized without the cooperation, input, and participation of all public, private, and community stakeholders.

-- Excerpt from World Trade Center Memorial Pedestrian Simulation Modeling Study Submission Form --

Overview

The development of the World Trade Center (WTC) Memorial site is one of the most important design projects in our country’s history. Since the WTC Memorial site is so sacred, the experience of individuals visiting the site has been an extremely important issue to the designers and planners. As a result, it was essential that the site provide the intended context: a peaceful, non-stressful environment to the thousands of visitors that are expected to visit on a daily basis.

As part of the design process, The Lower Manhattan Development Corporation (LMDC) and National September 11 Memorial & Museum at the World Trade Center began a joint interdisciplinary effort in August 2005 to study the movement of pedestrians on the WTC Memorial site. It is anticipated in the future that a large number of visitors (tourists), employees (office workers or shoppers from any of the proposed five towers), and commuters (that do not stop on the site) would traverse the WTC Memorial site throughout the day. This complicates matters because each of these groups have different reasons for entering the site with different walking characteristics.

A detailed methodology was used to analyze the projected pedestrian activity on the WTC site including the 2-dimensional (2D) real-time software used to provide a graphical representation of people’s movements across the site have been provided. In addition, several key issues were examined including an evaluation of the physical design (queuing, ticketing, landscaping, etc.), visitor experience, operational efficiency, and security and safety concerns through the use of this customized and finely grained procedure. The analysis results have enabled planners, designers, and developers to visualize and measure the functionality of the WTC Memorial site from a pedestrian perspective including how these pedestrians affect the entire WTC site.

CSS Qualities: Process

The number of design iterations and costs were greatly reduced because of data produced from the model output. For example, the footprint of the building proposed for the site was reconfigured in comparison to the original design scheme since the model results identified locations that were projected to be underutilized within the building. The designers were able to take this information and reconfigure the building footprint by more efficiently using the available space in comparison to the previous design. This is especially valuable since space within the WTC Memorial site is extremely limited. There are other examples that use the model results as part of the design process. The identification of under and over utilized space on the plaza was used to reduce crowding throughout the site. Walking paths were identified across the site and pedestrian conflict points were minimized or eliminated by modifying the design. Based upon the model results, the designers were able to strategically place or rearrange landscaping on the site to help control or redirect pedestrian desire paths as a means to reduce congestion and preserve the integrity of the site. Specifically, landscaping was used to deflect pedestrians around the lawn instead of allowing them to walk through it. The model data was used to optimize the placement of directional and informational signs across the site. The location and lengths of pedestrian queues were determined based upon the peak hour demand, availability of space, and the effect the queues would have on pedestrian site traffic. The model data was used to determine where bus waiting areas would interfere with pedestrians traveling along the adjacent sidewalk and recommendations were made to remedy any conflict points.

The development of detailed assumptions for the site was educational for the design team and planners because issues that would normally not be addressed in great detail until final design or after the site was about to be become operational were addressed in the early design phases of the process. Examples of this included the placement of signs, queuing, and landscaping. The process of identifying specific assumptions forced the design team and planners to make proactive decisions early in the process that would not have been made otherwise. This process was used as a "bridge" between planners and the design team and facilitated a unified design. The benefit of this would minimize the potential for design modifications further into the process that could be costly and could jeopardize the construction schedule. This required a monumental effort of cooperation between stakeholders in terms of not only providing valuable data but making compromises in the design to preserve the intended context of the site. The modeling project was used as a catalyst to initiate dialogue between stakeholders early in the process.

CSS Qualities: Outcomes

The design costs and number of design iterations were reduced based upon data that has been provided by the modeling of the WTC Memorial site. In addition, the overall cost to construct the WTC Memorial site could be reduced by some of the proposed design modifications. By modeling important public pedestrian spaces like the WTC Memorial site, a new and unprecedented level of pedestrian planning and compromise is brought to the design process. Incorporating the pedestrian modeling element early on can greatly improve the pedestrian experience and reduce costs of the project.

The project was innovative as it provided the ability to evaluate a complex pedestrian environment, analyze the site to ‘scale’ in two-dimensions, model real time pedestrian movements, accurately depict pedestrian movements on the site, model pedestrian behavior, included pedestrians as part of the design process, and to determine whether the design could adequately accommodate the projected number of visitors to the site. Both planners and the design team have appreciated how much the modeling effort has helped to guide the design to best suit the needs of the pedestrians traveling to, from, and through the WTC Memorial site.

   WTC Memorial Pedestrian Study