A Model for Joint Choice of Airport and Ground Access Mode

11th National Transportation Planning Applications ConferenceMay 6-10, 2007, Daytona Beach, Florida

Session 14: Hot and Cool Topics in Travel Modeling

Surabhi Gupta, Peter Vovsha and Robert Donnelly

Motivation for Focus on Air Passenger Demand Problem: Regional Models lack capability to analyze

changes to airports and/or ground access modes

How are airports typically treated in a regional model? Employment Centers (for work trips) Special Generator type estimation (for non-work trips) Distortions for sub-areas adjacent to airports

Distinctive characteristics of trips to/from airport Different from everyday activities Market includes non-residents/visitors Higher willingness to pay for some segments

FAA Regional Airport Study: Phase I

Preliminary Joint Airport Choice and Mode of Access model developed and tested for NY Region

Developed in order to illustrate the utility of the approach for a possible subsequent more intensive phase of air passenger demand analysis, and to

Provide an initial modeling tool for air passenger demand analysis with respect to airport operations, aviation service measures and pricing, and ground access characteristics

Estimation: Air Passenger Survey – 2005 NY BPM travel time and costs (approximate) Airport service and cost attributes (limited)

Literature Review

Pels et al.(1998) Airport-Access mode- Airline NL model Business vs leisure

Hess and Polak Airport Choice (2005) - Business vs Leisure,

Resident vs Visitor Airport-Airline-Access mode (2004) – Business

travelers only Basar and Bhat (2004)

MNL vs PCMNL model for airport choice

FAA Regional Study - 9 Airports John F Kennedy (JFK) La Guardia (LGA) Newark Liberty Int’l (EWR)

Long Island MacArthur (ISP) Westchester County (HPN) Stewart Int’l (SWF) Trenton Mercer (TTN) Atlantic City Int’l (ACY) Lehigh Valley Int’l (ABE)

8 Ground Access Modes

Auto Drop Off/ Pick up

Auto Park

Taxi Cabs

Local Bus

Shared Van

Rail Transit

Rental Car

Chartered Bus

Model Structure

Nested Logit Model Upper Level- Airport Lower Level – Access Mode Nesting Coefficient <1 could not be estimated

72 alternatives = 9 airports x 8 access modes, out of which 68 are available and 65 were observed

Explanatory Variables Airport Characteristics – size, domestic yield,

delays, gauge, river crossings, distance, access mode logsum ..

Access Mode Characteristics – travel time, cost, parking cost, income, age, gender, group size

Variables Used Compared with other models

Variables PB Study Hess & Polak (2004)

Pels et al. (1998)

Access Time, Access cost

Flight frequency

Seats (or Gauge)

Number of Flights

Airport-specific coefficients

Cross-coefficients

Constants

Average Yield or fare cost

Average Delay at Airports

Mode Specific Constants

Socio-economic variables

Segmentation Business only

Air Passenger Segmentation

Travel Purpose Business Non Business

Destination International Domestic

Traveler Resident Visitor

− Full Segmentation− Behavioral differences

− Partial Segmentation− US Market is price comparable− Domestic travel distances are

comparable to international

− Partial Segmentation− Restricted choice sets− Fundamental behavior is

similar (every passenger is both)

Estimation Results: Airport ChoiceBusiness Non-Business

Impedance Distance Distance^1.5

-0.0640.002

-8.03.2

-0.0680.003

-15.37.5

River Crossings Hudson -1.207 -24.4 -0.918 -29.7 East River/ Harlem River

-0.109 -1.6 -0.008 -0.3

Delaware River -0.905 -4.1 -0.660 -4.3

Attractions

Average Yield -5.368 -3.6 -16.128

-25.0

Average Delay (min) -0.007 -2.8 -0.005 -4.0

# International Airports Served

0.002 1.3

Airport Size (logged)

Number of flights 1 1

Domestic Gauge 0.167 1.1

Estimation Results: Access Mode Choice

Business Non-Business

Airtrain Present- Rail 2.166 10.6 1.517 14.3

Rental Cars - Manhattan -2.492 -15.7 -1.889 -12.3

Log -Number of Flights    

Taxi 0.546 8.7 0.605 13.7

Shared Van 0.413 3.1 0.670 6.6

Log -Number of Domestic Flights

   

Local Bus 1.970 2.4 3.084 7.3

Value of Time Estimates

Airport- Ground Access Choice Model (2005) Business: $62.6/hr Non-Business: $41.0/hr

NYMTC Regional Model (1997) Commuter: $15.8/hr Non-Commuter: $10-$12/hr

Confirmation from other research (business): Hess & Polak, 1995 ($93-$155/hr) Pels Nijkamp & Rietveld, 1995 ($120-$170/hr) Furuichi & Koppelman, 1994 ($72.6/hr)

Summary of Behavioral Observations

Segment Prefer Do Not Prefer

Residents (vs Non-Resident)

Auto Park, Local Bus

Rental Car, Taxi, Shared Ride, Rail, Chartered Bus

International (vs domestic)

Taxis, Shared Ride, Chartered Buses

Rental Cars, Auto Park

Female (vs Male) Auto Park, Rental Car, Transit (Rail and Bus)*

Group Size>= 2 Rental Car*, Chartered Bus

Rail, Taxi, Local Bus*

Age (< 35 yrs) Rail*, Taxis* Auto Park, Rental Cars

Age (> 55 yrs) Auto Park, Rental Cars, Rail, Local Bus

*For Non-business trips only

Auto Drop-off/Pick-up is Reference point

Impact of Income

Low income groups (< 60K) Less likely - Taxis, Rental cars, Auto park Non-Availability of car or higher travel costs Prefer public transportation (rail and bus)

High income groups (>140 K) Prefer Taxis Less likely to use Shared Ride, Local Buses Also prefer Auto Park, Rental Cars, Rail transit for

Non-business trips

Future Development

The model has been applied as a sample enumeration model, meaning it adjusts (or “pivots-off”) observed or baseline forecast shares based on changes to either the ground access or the airport measures for a given planning scenario.

The preliminary model has demonstrated the utility of a joint airport choice and mode of access analysis for airport ground access and operations planning

Possible further development in subsequent planning phases, including: Development of additional airport related measures of

capacity, service, and costs Refinement in network (skim) ground access travel

times and costs Re-estimation of the model with these added variables

Incorporate model as a Special Generator in the Regional NY Model