Handbook to Assess the Impacts of Constrained Parking at Airports (2010)

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16 Airport parking becomes constrained when the demand for parking spaces exceeds the available supply. The nature and severity of parking constraints vary from airport to air- port depending on factors that affect the balance between supply and demand. These factors include total parking sup- ply relative to total demand, the allocation of parking supply relative to the demand for specific parking products, airport operator policies pertaining to providing and operating park- ing facilities, the availability of alternatives to driving and parking at the airport for both airline passengers and airport employees, and external policies affecting the airport. The types of constrained parking, causes of constrained parking, and related consequences are discussed in this chapter. Types of Airport Parking Constraints Because it is impractical to manage a parking operation at 100% occupancy, airport operators typically define parking as constrained when occupancy exceeds a set percentage of capacity, based on operational experience. This percentage is referred to as the “functional capacity” of a parking facility or parking system. The functional capacity of parking facilities varies by airport, but generally ranges between 85% and 95% of supply. Regardless of the specific percent defined, once an airport operator considers parking to be constrained, the oper- ator will make decisions related to parking based on this prem- ise. It is the point at which the airport operator acts in response to the functional capacity constraint that is the key to defining whether or not an airport is operating in a constrained parking environment. Generally, public and employee parking con- straints result from an imbalance between parking supply and demand under one of the three scenarios that follow: • Inadequate total parking supply—Constrained parking occurs when the total demand for public parking or employee parking exceeds the functional capacity of the total available parking supply. • Lack of supply at an individual parking facility—Con- strained parking occurs when individual public or employee parking facilities do not accommodate the demand for park- ing at those facilities, while other facilities have excess capac- ity. For example, during peak leisure travel times, such as weekends and holiday periods, a short-term or daily parking facility may have excess capacity while the economy parking facility is constrained. This scenario differs from the previ- ous scenario in that the total airport parking supply may be adequate to accommodate total parking demand, but the allocation of supply among facilities does not meet demand. • Imbalanced allocation of parking supply—Parking allo- cated for specific uses does not accommodate demand dur- ing certain periods while parking capacity for other uses is sufficient or underutilized. The distinction between this scenario and the previous scenario is that multiple parking products or uses may be allocated to one facility. For exam- ple, many airport operators issue parking permits for air- port employees to use terminal area public parking. Other airport operators designate a section of terminal area park- ing for short-term parking, with the remainder designated for long-term parking. Parking constraints may occur occasionally or on an ongoing basis. Ongoing parking constraints typically occur on a weekly basis during busy periods whereas occasional parking constraints result from nontypical events, such as holiday periods, school vacations, or other events that generate non- routine spikes in airline passenger activity. Strategies to address ongoing and short-term parking constraints are discussed in Chapter 5. Causes of Airport Parking Constraints Insufficient capacity is only one of the reasons an airport may experience constrained parking. Constrained parking con- ditions occur when the balance between supply and demand C H A P T E R 2 Constrained Airport Parking Environment

17 changes such that either (1) supply decreases (or does not increase at an adequate rate) relative to demand or (2) demand increases relative to supply. Many factors can influence both sides of this equation (e.g., a low-cost carrier begins serving the airport and stimulates demand for airline travel, or a pub- lic or employee parking lot is redeveloped for another use with no replacement supply). Therefore, it is important that parking capacity and parking demand be analyzed together when assessing the causes of constrained parking and when subsequently making informed decisions about the best ways to resolve constrained parking at a specific airport. The typi- cal causes of constrained public or employee parking at air- ports are discussed in the following section. Parking Supply Constraints The parking supply at an airport may be limited for the following reasons: • Land constraints may limit the physical area available for the development of on- or off-airport parking facilities, such as at airports where land is not available or ideal to accommodate parking, either on the airport property or in the vicinity of the airport. • Financial constraints may limit the ability of an airport operator or a private operator to expand parking supply. Parking revenue is generally a significant component of an airport’s financial operation and overall airport financial constraints are a major consideration when evaluating future airport parking expansion, particularly if a parking structure is under consideration. Although a new, structured parking facility at a constrained airport would likely result in incre- mental revenue, the resulting increase in an airport’s debt service to finance a parking structure without sufficient off- setting incremental parking revenues in the initial years of operation could negatively impact an airport’s overall debt service coverage ratio; thus, potentially increasing an airport operator’s cost of capital. • Airport operator policies and regulations may limit the ability of the airport operator to expand the parking sup- ply for financial, land use, environmental, or other reasons. These policies may not relate directly to parking, but they influence the parking environment. For example, a land- use designation or policy to support rental car operations in the terminal area—land that could otherwise be used to accommodate parking demand—is an airport operator policy that could indirectly contribute to a constrained parking environment. • External policies and regulations related to land use, airline passenger vehicle trip reduction, employee trip reduction, and other issues may limit the ability of an air- port operator or private off-airport operator to expand the parking supply. For example, an externally enacted policy may restrict airport parking to encourage the use of public transportation; however, this policy may result in a parking constraint if the public transportation system does not offer the level of service or geographic coverage necessary to serve the airport’s parking customers. Influences on Parking Demand Demand for airport parking may exceed supply for the fol- lowing reasons: • An inadequate allocation of parking supply may result in the demand for a certain parking product at an airport exceeding the supply of that product as a result of an imbalance in demand relative to the available supply. This imbalance could occur on a regular basis or sporadically, such as during peak days of the week or at peak seasons of the year. For example, increased leisure travel in the sum- mer months may result in increased demand for economy Allocation Constraint at Seattle-Tacoma International Airport Seattle-Tacoma International Airport has one public parking facility—an eight-level parking garage adjacent to the terminal area with designated areas for short-term parking, premium parking, and long-term parking. Employees with parking permits for the garage were able to access any available long-term space. In 2007, the Port of Seattle reallocated the number of spaces by product to achieve more efficient use of the garage. The reallocation included combining the hourly and premium parking areas, and requiring employees to park on the eighth floor. The eighth floor had been underutilized by revenue-generating customers who perceived it as being remote. The reallocation resulted in the availability of additional lower-level spaces for revenue customers, a more consistent and dedicated park- ing space supply for employees, improved overall use of the parking garage, and a reduction in the number of spaces dedicated to short-term and premium parking by cross-utilizing a combined, but smaller, inventory for those parking products. (6)

parking, thereby resulting in a constrained parking condi- tion at that facility, while excess capacity exists in terminal area parking facilities. • A nonoptimized rate structure can contribute to parking constraints if the differential in rates between parking products is too narrow or the parking products are not priced to effectively allocate and balance demand among parking products and other airport ground access modes. For example, parking rates for all parking products may be low in comparison to alternative ground access modes, which might result in a high proportion of airline passen- gers choosing to park rather than use alternative modes of ground access. • Changes in airline service directly affect public parking demand. For example, the introduction of low-fare airline service at several airports has been shown to result in increased airport parking demand relative to the demand typically expected from legacy airline service. This increase results from several factors, including the effect of increasing the potential catchment area of an airport to airline passen- gers that typically would not travel by airline or travel at all. This change has resulted in a higher proportion of passen- gers that drive longer distances and that have a higher propensity to park at the airport. Also, an increase in the number of budget-minded airline passengers that can justify paying for long-term parking when considering the low cost of the airline ticket has a tendency to increase parking demand. In addition to the effect of low-cost carrier service, changes in airline schedules have an effect on the peaking patterns at parking facilities throughout the day, which can affect the availability of parking for greeters and well-wish- ers during peak periods. • External policy influences can contribute to changes in parking demand at an airport. For example, local jurisdictions that have enacted legislation to promote employee trip reductions can affect airport employee park- ing demand. • Effects of previous experiences with congestion are a con- sideration for airline passengers deciding on an airport access mode. For example, ongoing airport parking con- straints may have artificially affected airport mode choice, resulting in pent-up demand that should be considered when developing solutions to constrained parking. Simi- larly, regional roadway congestion may change airline passenger travel behavior such that future regional improvements may result in changes in airport access and parking use. • Lack of ground access mode alternatives to the private automobile may result in higher demand for parking facil- ities and, thus, a constrained parking environment at the air- port. Alternative access modes may be viable if they are consistent with the following service characteristics: – Offer service hours and frequencies in alignment with airline passenger flight schedules or employee work schedules, – Provide geographic coverage for airline passenger ori- gins or employee residences, – Offer fares that are acceptable in relation to the cost of driving and parking, and – Present reasonable travel times in comparison to the private automobile. As discussed in Chapter 1, it is important to note that the cost of alternative modes of access and the time differential for an alternative mode compared with driving and parking at the airport are valued differently by business and nonbusiness airline passengers. Therefore, policies designed to address demand-side constraints will be more likely to achieve the desired results if targeted to the market segmentation of the airport’s O&D airline passengers. Effects and Consequences of Constrained Airport Parking Consequences resulting from constrained airport parking are described in the rest of this section. Customer Satisfaction Parking customers who cannot easily find a parking space or are consistently diverted to other parking facilities must allow more lead time to travel to the airport. In many cases, the cus- 18 Causes of Airport Parking Constraints, Non-Airport Policies and Regulations, Portland International Airport The Port of Portland operates Portland International Airport (PDX) under a conditional land-use permit from the City of Portland, Oregon, which, among other things, limits the number of pub- lic parking spaces that can be added at PDX and specifies where the spaces can be provided. The permit also requires the Port to charge airport employees a fee to park at PDX. The most recent permit was issued in 2003. (12)

tomer is unaware of the constraint until arriving at the airport, which can lead to an undesirable effect on travel plans, includ- ing missed flights. Increased travel time and frustration may make driving and parking at the airport less appealing in com- parison to other modes of travel, including the use of a pri- vately operated parking facility that competes for airport parking customers (where available). Airport operators may find it difficult to entice parking customers to return to on-air- port parking facilities once those customers have chosen to park off-airport or use alternative airport access modes. Park- ing customers may choose to use alternative modes or privately operated parking facilities in the future, even during periods when parking at the airport is not constrained, which translates to lost parking revenue for the airport operator. Airport Roadway Traffic Congestion Airline passengers who would typically choose to park their vehicles may choose another mode to access the airport if they anticipate constrained airport parking. These changes may affect airport roadway traffic in the following ways: • If an airline passenger is traveling from one parking facility to another while searching for a parking space, that passen- ger is adding vehicle traffic to the airport roadway system. • If an airline passenger shifts from parking to being picked up and dropped off by private automobile for future trips, that airline passenger (or airline passenger party) will generate twice the number of vehicle trips—in the region, on local roadways surrounding the airport, and on the airport road- way system—than were generated when the automobile was driven to the airport and parked by the airline passenger. For each airline round trip during which the passenger party parks for the trip duration, a one-way vehicle trip is made to the airport when the airline passenger party departs, and a one-way trip is made from the airport when the airline pas- senger party returns. Conversely, when an airline passenger party is dropped off by private automobile, one two-way vehicle trip is made to and from the airport to accommo- date the enplaning trip, and another two-way vehicle trip is made to and from the airport to pick up the same party upon its return. Similarly, a shift from parking to taxicab or single-party limousine mode also results in an increase in the total number of trips on the roadway system; how- ever, the increase will not be twofold given that a portion of the taxicabs and limousines carrying an airline passen- ger party to the airport will transport a different airline passenger party departing the airport. • If an airline passenger shifts from parking to an HOV mode, the number of vehicle trips in the region, on local roadways surrounding the airport, and on the airport roadway system decreases. In this case, the effect of constrained parking improves roadway traffic conditions. • During constrained parking conditions, greeters who are picking up an arriving passenger and can not find a parking space may drive to the terminal curbside to pick up the arriv- ing passenger. If the arriving airline passenger is not ready for pickup, the driver may be required to circle around the ter- minal area or travel to a cell phone lot (if available) until the airline passenger is ready to be picked up, which increases vehicle circulation on airport roadways. Increased vehicle traffic and associated curbside conges- tion directly translate into increased vehicle emissions, as dis- cussed in the following section. Increased Vehicle Emissions Total vehicle miles traveled (VMT) on the airport and the resulting emissions increase during constrained parking con- 19 Causes of Airport Parking Constraints, Nonoptimal Rate Structure, Chicago O’Hare International Airport Prior to December 2007, the rate for the daily parking product at Chicago O’Hare International Airport’s domestic terminals was $30 per day, equivalent to the rate for parking at the inter- national terminal’s short-term facility, which was intended to accommodate greeters and well- wishers. When daily parking facilities at the domestic terminals reached functional capacity and were closed, some parking customers diverted to the international terminal’s short-term facility rather than to the remote economy parking products. These diversions were suspected to be the cause of constrained condi- tions at the international terminal’s short-term parking facility. In December 2007, the parking rate at the inter- national terminal’s short-term lot was increased to $50 per day to discourage this unintended diversion of parkers. The new rate matched the daily rate for the hourly parking (short-term) product at the domestic ter- minals. Airport staff believe that this rate increase was successful in achieving their goal, and closures of the international terminal short-term lot have been reduced. (2)

ditions for the reasons described in the previous section. Increased air pollutant emissions also occur when a parking customer is forced to circulate within a parking facility while searching for an available space. When airline passengers shift from parking to pickup and drop-off by private automobile, taxicab, or single-party lim- ousine, the increased vehicle trips resulting from this mode shift generate more vehicle emissions on the airport and within the region than would be the case if these airline pas- sengers parked for the duration of their trips. However, if the vehicle used in the drop-off and pickup mode generates lower vehicle emissions as the result of cleaner fuel technology than the vehicle that would have been parked, then the net change in emissions generated should be considered. For shifts from airline passengers parking for the duration of their trips to HOV modes, the vehicle emissions generated should decrease. In this case, the effect of constrained park- ing may have a positive effect on vehicle emissions. Increased Costs Constrained parking conditions often require increased management on the part of the airport operator (or its park- ing operator) to direct parking customers from a temporarily closed facility to an open facility or to actively assist customers in finding an available space within a constrained facility. This increased management results in increased labor costs. When temporary overflow facilities are opened to accommodate excess parking demand, additional labor and operational costs will be incurred, including busing costs associated with opera- tion of remote overflow lots and the costs associated with rev- enue collection, if applicable. Transportation will be required between the terminal area and the overflow facility until the driver of the last parked automobile returns from his or her trip. Lost Revenue Constrained parking generally results in lost airport rev- enue. For example, a missed revenue opportunity occurs for every parking customer that chooses to (1) shift from the pub- lic parking supply in favor of other modes, (2) downgrade to a remote facility at which a lower rate is charged, or (3) move to a privately operated off-airport parking facility. Potential Diversion to Other Airports Data from the stated preference survey conducted as part of this research project indicate that constrained parking is not a primary reason for airline passengers choosing one airport over another in an airport system. The primary reasons airline passengers choose one airport over another in a competing airport system are the availability of direct flights to a desired destination, the price of airline tickets, and flight travel time. Airport Employee Retention Airport employees are vital to the operation of an airport. One of the challenges airport employers face in recruiting and retaining employees is the availability of viable commute alter- natives to the private automobile that accommodate work schedules. This is particularly true for part-time and temporary workers. Therefore, commute options to the airport must be convenient compared to commute options to other employ- ment centers, such as a downtown area that is well served by public transportation. If the employee parking supply is con- strained and the alternatives to driving do not accommodate work schedules or represent a significant time penalty com- pared to driving, airport employers will have a difficult time recruiting and retaining employees. 20