massive uncertainty
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Massive Uncertainty. Dr. Richard de Neufville Professor of Engineering Systems and Civil and Environmental Engineering Massachusetts Institute of Technology. Massive Uncertainty. Objective: To present realistic context of forecasting exercise Topics Evidence Consequences. - PowerPoint PPT PresentationTRANSCRIPT
Airport Systems Planning & Design / RdN
Massive Uncertainty
Dr. Richard de Neufville
Professor of Engineering Systems andCivil and Environmental Engineering
Massachusetts Institute of Technology
Airport Systems Planning & Design / RdN
Massive Uncertainty
Objective: To present realistic context of forecasting exercise
Topics Evidence Consequences
Airport Systems Planning & Design / RdN
Causes of Uncertainty
Underlying variability of phenomenon
Difficulties in measurement or estimation
Unforeseen or “unpredictable” circumstances
Limits to valid measurement for example: behavioral patterns
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Evidence
1. Simple Physical Systems
2. Overall Traffic
3. Local Traffic (Worse)
4. Other Operations
Airport Systems Planning & Design / RdN
Ratio of Real Costs to Estimated Costs for Airport Projects
0
5
10
15
0 0.5 1 1.5 2 2.5
Median ~= 1.25
Real/Estimated Cost Ratio
Perc
ent
of O
ccur
renc
es
Costs expressed in constant dollars
Airport Systems Planning & Design / RdN
Cost of asphalt rising Local road repairs are likely to lag
By Kay Lazar, Globe Correspondent June 8, 2006http://www.boston.com/news/local/articles/2006/06/08/
cost_of_asphalt_rising/
The soaring cost of petroleum -- a primary ingredient of asphalt -- has forced many communities to shoulder a 50 percent increase in costs as crews head out to repave roads this summer. Asphalt sticker shock is creating heartburn for legions of highway chiefs, prompting many to significantly curtail the number of roads they intend to repair this season.
And the going may get even tougher. Two major asphalt suppliers for the region are warning of another 50 percent increase by Thanksgiving -- in addition to potential shortages
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Cost Growth for Various Projects
DOD60 HWAY WATER BLDNG DOD50 ADHOC MAJOR ENRGY NASA NASA AVG St.Dev.
3.0
2.5
2.0
1.5
1.0
0.5
0.0Rat
io o
f Act
ual t
o Es
timat
ed C
ost
CONST SAT g
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NASA Projects Cost Growth
HST GLL UARS GRO COBE MGL MOBS LSAT EUVE ERBE AVG St.Dev.
3.5
3.0
2.5
2.0
1.5
1.0
0.5
0.0Rat
io o
f Act
ual t
o Es
timat
ed C
ost
Airport Systems Planning & Design / RdN
Errors in 5 year TAF
00.20.40.6
0.81
1.2
0 10 20 30 40 50
Percent error (Absolute value)
Cum
ulat
ive
Dist
ribut
ion
Adapted from: Terminal Area Forecast (TAF) Accuracy Assessment Results
Jerome Friedman, MITRE CAASD, Sept. 30, 2004
Results of a 2004 study
Airport Systems Planning & Design / RdN
Results of a 2004 study
Errors in 5 year TAF
0
5
10
15
20
Percent Error (Absolute value)
Freg
quen
cy o
f Err
or (%
)
Adapted from: Terminal Area Forecast (TAF) Accuracy Assessment ResultsJerome Friedman, MITRE CAASD, Sept. 30, 2004
Airport Systems Planning & Design / RdN
Recent Error Data from U.S Source: MITRE CAASD and FAA
City92 93 94 9597 98 99 2000
ATL 10.8 -10 -15.5 -13.3BOS -0.8 -2.1 -0.2 8.9BWI 27.4 6.3 -5.8 7.5CLE -13.4 -14.6 -17.5 -13.3CLT 7.8 15.8 10.9 18.1CVG -0.9 -4.3 -14.5 -9.5DCA 7.5 13.8 2.7 -5.1DEN 18 19.6 19.9 5.5DFW 2.6 -3.2 7.8 14.2DTW -13.2 -6.5 -8.6 3.1EWR -12.2 -5.9 -0.1 5FLL 17.2 3.4 -3.8 -11.6HNL 28.2 40.9 23 14.9IAD -6.4 -9.5 -41.4 -41.2IAH -8.1 -12.3 -8.9 -25.4JFK -0.9 6.2 11.7 3.8
5 YEAR FORECAST FROM / TO
Airport Systems Planning & Design / RdN
Recent Error Data from U.S Source: MITRE CAASD and FAA
LAS -5.1 -2.2 -10.4 8.5LAX 2.2 -1.6 -1.4 0.6LGA 7.7 3.9 -3.2 -4.8MCO 15.9 15.1 18.6 14.9MDW 33.9 -21.3 -32.9 -5.2MEM 9.1 16.3 10 4.7MIA 3.9 3.8 13.1 21.5MSP -5.4 0.4 5.6 0ORD -6.8 -5.1 -3.4 2PDX -3.9 -12.2 -9.5 3.5PHL -3.2 -7.2 -4.2 0.1PHX 6.1 6 4.1 -2.8PIT 9.4 9.9 8.2 6.6SAN 21.6 20 15.6 20.6SEA 6.3 -0.8 -15.3 -9.3SFO 25.7 22.5 17.4 10.7SLC -6.7 -0.2 -0.3 9.8STL -7.4 -1.3 -3.3 4.9TPA 16.5 12.4 6.9 5.6
City92 93 94 9597 98 99 2000
5 YEAR FORECAST FROM / TO
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Actual vs. Forecast 10 years earlierSource: FAA Aerospace Forecast FY 2006-2017
Domestic Commercial Emplanements Year being forecast Actual vs. Forecast 1995 11.4 1996 12.2 1997 17.4 1998 14.9 1999 9.9 2000 5.5 2001 4.7 2002 14.5 2003 12.5 2004 20.0 2005 13.9 Median and Average 12.5
Note: These are aggregate NATIONAL data, in which greater local variations tend to cancel each other out
Airport Systems Planning & Design / RdN
Older FAA Forecasts vs. Actual Data (% Difference)
Review of the FAA 1982 National Airspace System Plan
Forecast Year
For Year
Commercial Enplnmnts.
Revenue Pax. Miles
Hrs. General Aviation
GA Ops at FAA Towers
Tot. Ops at FAA Towers
1959 1964 (1.30) (6.50) (0.60) 4.60 9.701960 1965 (9.50) (9.70) (1.20) (27.80) (21.60)1961 1966 (27.50) (26.00) (15.30) (37.70) (28.90)1962 1967 (32.10) (31.40) (23.60) (34.70) (27.30)1963 1968 (41.30) (41.30) * (38.40) (32.50)1964 1969 (31.40) (33.60) (23.50) (27.30) (24.90)1965 1970 (14.10) (19.80) (16.30) (2.60) (5.20)1966 1971 9.40 0.50 (1.60) 53.70 42.201967 1972 23.60 13.00 9.10 72.50 54.901968 1973 23.90 15.90 7.40 78.30 58.401969 1974 21.10 21.20 4.60 53.60 42.401970 1975 26.30 33.00 (0.60) 80.90 25.901971 1976 19.00 28.60 (0.60) 42.90 22.901972 1977 22.30 33.70 (6.80) 36.90 4.501973 1978 14.00 18.30 (10.40) 14.80 8.801974 1979 (9.70) (7.40) (13.70) 11.80 9.401975 1980 (10.60) (17.30) (0.20) 34.60 25.701976 1981 4.30 (1.80) 15.70 41.30 32.10
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Forecast vs. Actual International Pax in Japan
Forecast Passengers (million) Percent ErrorFor Done In Actual Forecast Difference/Actual
1980 1970 12.1 20.0 651985 1975 17.6 27.0 531990 1980 31.0 39.5 271995 1985 43.6 37.9 (13)
Airport Systems Planning & Design / RdN
Forecast vs. ActualInternational Pax to Japan
0
50,000
100,000
150,000
200,000
250,000
300,000
350,000
400,000
450,000
1955 1960 1965 1970 1975 1980 1985 1990 1995 2000
Year
10,0
00 to
n
Actual Forecast
Airport Systems Planning & Design / RdN
Forecast vs Actual International Pax in Sydney
Source of Forecast, in YearForecastFor Year Consultant
1974
Regional Study
1978
National Ministry
1983
1980 3.77 2.98 - 3.46
1985 7.4 3.87 - 4.34 2.674 - 3.047
1990 9.8 4.71 - 5.51 2.762 - 3.751
2000 projected 12.0 6.27 - 8.66 2.938 - 5.159
2000 actual 10
Airport Systems Planning & Design / RdN
ACTIVE GENERAL AVIATION AIRCRAFT1980 FORECAST
0
100
200
300
400
70 72 74 76 78 80 82 84 86 88 90
NUM
BER
OF
AIR
CR
AFT
ACTUAL 80 FCST.
Airport Systems Planning & Design / RdN
ACTIVE GENERAL AVIATION AIRCRAFT1985 FORECAST
0
100
200
300
400
70 72 74 76 78 80 82 84 86 88 90 92 94
NUM
BER
OF
AIR
CR
AFT
ACTUAL 80 FCST. 85 FCST.
Airport Systems Planning & Design / RdN
ACTIVE GENERAL AVIATION AIRCRAFT1990 FORECAST
0
100
200
300
400
70 74 78 82 86 90 94 98
NUM
BER
OF
AIR
CR
AFT
ACTUAL 80 FCST. 85 FCST. 90 FCST.
Airport Systems Planning & Design / RdN
ACTIVE GENERAL AVIATION AIRCRAFT1998 FORECAST
0
100
200
300
400
70 74 78 82 86 90 94 98 02 06
NUM
BER
OF
AIR
CR
AFT
ACTUAL 80 FCST. 85 FCST.90 FCST. 98 FCST.
Airport Systems Planning & Design / RdN
Summary and Recommendations
Summary Forecast Errors have been large Likely to continue
Recommendations: Expensive Forecasting is cost-ineffective Use general trends ...With large ranges Flexible Approach to Planning!!!