# Exploring Virtual Environments to Assess the Quality of Public Spaces
## 3 Materials and Methods
### Measures: Indicators of Public Spaces Quality
#### 3.3.1 Pedestrian Level of Service PLOS--Trip Quality Method  
In general, the pedestrian level of service is a quantifiable measure that is typically prioritized in the assessment of public spaces and their pedestrian-environment interaction. PLOS can be measured both qualitatively and quantitatively using a multitude of methods and permits quantifying comfort and safety levels of existing and planned walkways allowing objective and sound evaluations of pedestrians' perception and response to roadway environment. Although the methods to analyze the pedestrian level of service are vast, a limitation is that it had to match the prompt of the experiment and thus had to be applicable to both a virtual environment and a static video of the real environment. The Trip Quality Method (TQM) [3] was thus chosen. The method allows raters to qualitatively rate a walkway from a pedestrian's perspective in regards to pleasantness, safety, and comfort using nine measures: enclosure/definition, complexity of the path network, building articulation, complexity of spaces, transparency, buffer, shade trees, overhands/awnings/varied roof lines, and the physical component/condition. For each of these factors, a score between 1 (very poor)and 5 (excellent) was assessed; afterward, the arithmetic average was taken to obtain a final score on the pedestrian level of service [4]. Additionally, [3] specified that the method is best served for city streets, shopping areas, and working spaces, all of which characterize the three points of view selected for the experiment. Unfortunately, not all nine measures are relevant to the experiment, as the experiment's static nature does not allow for the sufficient testing of certain factors. Due to the method's simplistic arithmetic nature, we were able to effectively manipulate by extracting the four most relevant characteristics and having our participants rate those on the same scale previously mentioned, and then calculating their arithmetic average to obtain a final score out of five, considered the pedestrian level of service. This score is later weighed with a letter grade based on the following conversion table. * LOS A = 4.0 to 5.0 = Very Pleasant;
* LOS B = 3.4 to 3.9 = Comfortable;
* LOS C = 2.8 to 3.3 = Acceptable;
* LOS D = 2.2 to 2.7 = Uncomfortable;
* LOS E = 1.6 to 2.1 = Unpleasant;
* LOS F = 1.1 to 1.5 = Very Unpleasant. The four factors studied in the experiment are the complexity of the path network, complexity of spaces, buffer areas, and shade and trees. In terms of complexity in the path network, the factor focuses on the path network being complete and easy to understand. This means that from being in a static position, the user is not confused by the path network and does not feel as though it is poorly connected. Thus, to quantify this factor in a way that is easily comprehensible for the general participant (as the participants are not required to have a level of prior knowledge in the subject), the question used was \"How simple is it to understand the pedestrian path network in the area?\". The second factor complexity of spaces is quite similar as it studies the completeness of the public space and its contribution to inducing simplicity in the comprehension of the functions of the space. The more complete the space is in terms of including all necessary features for its function, the more simple it is to understand said function. Spaces that can be studied with this factor include commercial districts, residential neighborhoods, courtyards, plazas, parks, and playgrounds. Objects that heavily influence the function of the public space include water features, trees, geometry, signs, street furniture, and any unique physical quantities of a public space. Places that miss these defining features are typically more difficult to understand, making them more complex. To best assess this factor, the question used in the questionnaire is \"How simple is it to understand the function of the surrounding public spaces in the area?\".