June 2004 DOT HS 809 736 

Forecasts of Crash Fatalities During 

Summer Holiday Periods in 2004

Cejun Liu* and Chou-Lin Chen 

Traffic Safety Facts

Research Note

National Center for Statistics and Analysis 400 Seventh St., S.W., Washington, D.C. 20590 

Generally, the fatality rates are higher during holiday periods than during non-holiday periods [1, 2]. 

Analysis and forecasting of the fatality rates during 

holiday periods are useful for providing warnings that 

may reduce fatalities. In preceding work, two time 

series techniques, Holt-Winters (HW) Algorithm and 

Autoregressive Moving Average Model (ARMA), had 

been employed to analyze and forecast the fatality 

counts during holiday periods [2]. For three summer 

holiday periods in 2003, two forecasts were made based 

on 1982-2002 historical data. In Table 1, these forecasts are compared with the FARS (Fatality Analysis 

Reporting System) 2003 Early Assessment File (EAF)‡, 

to examine the accuracy of the forecasts. 

Table 1

Fatalities in Three Summer Holiday Periods in 2003

 Holiday FARS Forecasts

 Period 2003 EAF* HW ARMA

Memorial Day 497 508 504

 4th of July 552 537 564

 Labor Day 541 526 545

 Total 1590 1571 1613

Note: * Early Assessment Files (EAF) of FARS.

In this report, we provide our estimates of fatality counts 

for three summer holiday periods in 2004. Two similar time series techniques [2] are used to do the analyses 

and forecasts based on 1982-2002 historical data and 2003 

EAF files data. That is, the forecasts are based on an inferred study of past general data behavior over time (time 

series). The fatality counts for 1998-2003 are shown in 

Table 2, along with the HW and ARMA forecasts for 2004.

Table 2

Three Summer Holiday Periods’ Fatality Counts for 

1998-2003 and Fatality Forecasts for 2004

 Memorial 4th of July

 Year Day (days) Labor Day

 98 393 479 (3) 464

 99 500 509 (3) 485

 00 466 717 (4) 529

 01 515 207 (1) 481

 02 491 683 (4) 541

 03* 497 552 (3) 541

 04 HW: 511 HW: 547 HW: 546 

 ARMA: 506 ARMA: 564 ARMA: 545

 95% C.L. 95% C.L. 95% C.L.

 (417, 595) (419, 709) (468, 622)

Notes: * 2003 Early Assessment Files of FARS.

Three Summer Holiday Periods in 2004

Memorial: 6:00 pm Fri. 05/28/04 to 

5:59 am Tue. 06/01/04

4th of July: 6:00 pm Fri. 07/02/04 to 

5:59 am Tue. 07/06/04

Labor Day: 6:00 pm Fri. 09/03/04 to 

5:59 am Tue. 09/07/04

‡ Subject to change when the final files of FARS 2003 are available. 
National Center for Statistics and Analysis 400 Seventh St., S.W., Washington, D.C. 20590 

For additional copies of this report, please call 1-800-934-8517 

or fax your request to (202) 366-3189. For questions regarding 

the data reported in this report, contact Cejun Liu [202-366-

5354] or Chou-Lin Chen [202-366-1048]. Internet users may 

access this report and other general information on highway 

traffic safety at: http://www-nrd.nhtsa.dot.gov/departments/

nrd-30/ncsa/AvailInf.html

[1] U.S. Department of Transportation, National Highway 

Traffic Safety Administration, National Center for Statistics 

and Analysis, <<Traffic Safety Facts 2002>>.

[2] Cejun Liu and Chou-Lin Chen, Time Series Analysis and 

Forecast of Crash Fatalities during Six Holiday Periods, U.S. 

Department of Transportation, National Highway Traffic 

Safety Administration, National Center for Statistics and 

Analysis, NHTSA Research Note DOT-HS- 809-718. 

*Cejun Liu is a Program Analyst employed by Rainbow Technology Inc., a contractor working for the Mathematical Analysis Division, National Center for Statistics 

and Analysis, NHTSA. Chou-Lin Chen is a Mathematical Statistician and team 

leader in the Mathematical Analysis Division, National Center for Statistics and 

Analysis, NHTSA.