Space

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Tags: airport design, wayfinding,
directionality, spatial configuration


     
            

Architects and planners have developed a number of tools and techniques to calibrate a passenger’s spatial experience of the airport.  The size and shape of design elements, from the form of the terminal building to the dimensions of the check-in counter, can dramatically influence a passengers perceptual experience.  The accurate forecasting of quantitative data, like the anticipated number of air travelers, as well as qualitative metrics, such as the amount of time the average passenger will tolerate waiting in line, is instrumental in guiding these design decisions.  As a result, airport stakeholders employ a number of strategies to estimate the overall number of passengers, and predict passenger preferences during the various phases of air travel.  

1. Form
   
2. Level of Service
   
3. Personal Space

Form

Though airports all share the same basic function, there is hardly such a thing as a typical airport layout. While passenger experience is of course a key design consideration, the form of each terminal is sculpted by a confluence of external factors including established flight paths, runway layouts, natural and urban contexts, and the potential for future airport expansion.

“While wayfinding is a significant aspect of air terminal design, the main determinant of the building’s overall form is the airport’s runways. These vast expanses of tarmac occupy most of the airport’s landmass, and they are relatively fixed once they have been developed” [1]. 

At the largest scale, the general configuration of an airport terminal influences key metrics such as the travel distance between the different aspects of the airport experience, including check-in, security and the departure lounge. The suggested maximum walking distance between major functions (eg. check-in to security; security to departure lounge) is 300m [2]. 

As a result, though many airport designs share similar spatial arrangements or typologies (ie. linear, pier, satellite, transporter) there is no consensus on the ideal spatial configuration, and airport designs show a high degree of formal diversity [3].  From the perspective of passenger experience, this wide catalog of design solutions means that there is no universal strategy for navigating an airport. Instead this diversity means that “problem-solving skills are demanded of passengers and visitors” for each new airport encountered [4].

Personal Space

Beyond estimating the quantitative aspects of passenger travel through the airport, a better understanding of more qualitative aspects - such as potential areas of crowding - can help airport stakeholders more precisely allocate space.  Research has often questioned the adequacy and robustness of the various quantitative standards. Odoni and de Neufville identified that one “problem with these standards is that they assume that the space provided for an activity will be useful, no matter how or where it is provided. Implicit in the formula is the idea that the occupants of a space somehow disperse to make use of an entire area. People are not gasses, however, and unfortunately no such physical law exists for them” [5].

Patterns of traffic concentration are “usually quite easy to anticipate, and avoid. People, for example, naturally cluster around information booths, the first queues in front of them in any set of parallel queues, the mouth of the baggage chute, telephone banks, etc. These facilities should thus not be sited where they could cause bottlenecks” [5]. The wide range of factors to consider is one reason for the difficulty in developing a universal approach.  One recent review of LOS metrics for departure lounges identified space available for circulation, number of available seats, and waiting time as key factors, but noted that concessions, lighting, announcements, comfort and aesthetics could all impact passenger perceptions of a terminal [11].  Adding to the complexity of quantifying passenger experience is that “...the same airport can be perceived differently: as a familiar or home airport for frequent patrons and a destination airport for other passengers ” [12].

A number of models have been developed to simulate passengers' behaviour inside airport terminals. Microscopic models focus on a reliable and detailed evaluation of the complex movements of every passenger [13] while macroscopic models analyze the nature of queues in general [14]..

Level of Service

“It easily and quite predictably happens that a terminal with enough space... in fact has a number of significant problem areas which make the building feel, and thus be, inadequate” [5].

A successfully designed airport terminal needs to satisfy the needs of three primary user groups: the passenger, the airline, and the operator of the airport.  Of these groups, passengers significantly outnumber other airport users and represent a significant source of airport revenue. In many ways they are the primary reason for the airport to exist. The accommodation of passenger needs is thus undoubtedly a key component of terminal design [6]. According to airport scholar and researcher Brian Edwards, a well-designed airport is defined as one in which “jaded passengers ferried from building to plane and terminal to gate, can find tranquillity and peace” [7].

For the last 50 years, airport stakeholders have sought to develop a method to evaluate the design and operation of terminals from a passenger experience perspective, frequently through level of service standards.  Level of Service (LOS) refers to the spatial and temporal framework developed by aviation stakeholders to explicitly specify the size of a particular space in the airport, and how much time a typical passenger should spend there. First developed in the 1970’s by the International Air Transport Association (IATA), the standards are intended to assist architects, engineers, airlines and airport owners in making design decisions and form the basis for translating demand forecasts into an architectural design [8]. The standards are generally expressed as letter grades - which reflect the percentage of passengers who will find a given wait time or amount of space adequate - and include per-occupant area requirements for both standing and walking behavior.

Odoni and de Neufville summarized the key decision embedded in this design process: “Higher standards imply more space and cost, and these have to be made compatible with the financial objectives of the owner or operator of the terminal. The level of detail at which the step is carried out varies greatly from airport to airport, and the results may also be very different” [5].

Despite the dramatic changes to the air travel experience over the last 50 years, the basic contours of LOS standards have remained largely unchanged since their inception [8]. However, the precise factors to include in a LOS evaluation are a subject of continual debate among airport stakeholders, and no universally accepted method exists for measuring LOS for airport terminal buildings [9]. 

Level of service standards often rely on a careful estimate of the rate at which passengers that will be flowing through a particular space in the terminal. For purposes of design, this forecasting relies on a metric known as the design hour. 

The design hour has historically been calculated via a number of different metrics, depending on the available data and the precise makeup of flights at a given airport.  One common approach defines the design hour as the 90-95th percentile busiest day of the year.  Determining this hour requires a data-intensive, precise tracking of passenger flows for each flight during the year to find the activity level which represents 90-95% of the maximum level of traffic.  Other approaches include defining the design hour as the peak hour, on an average day during the peak month [10].

“The objective of this exercise is to produce highly detailed, peak-hour demand scenarios for the design day many years ahead. These figures provide the basis for the actual design. It is a most speculative enterprise. This forecasting process normally first estimates aggregate traffic for the ‘target year’ for which a new, expanded or modified terminal is being designed. This aggregate forecast, in turn, is converted into a further estimate of traffic for the ‘design day,’ normally taken to be the 30th or 40th busiest day of the year, or something such as the ‘average weekday of the peak month’” [5].

What if?

A primary component of controlling the spread COVID-19 is preventing people from coming in close contact with each other, as inhalation of aerosolized virus particles from another person is the most common method of transmission.  It is an inherently spatial crisis.All preventative measures currently in place make use of increased physical distancing between individuals.Many facets of passenger experience of air travel will be modified to reflect this new spatial dynamic, including airport check-in, security, immigration, the departure lounge and boarding.Much like the borders and boundaries for sorting and screening established after 9/11, a post-COVID air travel experience will define new spatial relationships between individuals, and new ways of interacting with the physical space of the airport.