Lee, David Chung-Sang

Sharrah, Mark L.

Stahlman, Barbara A.

eScholarship - University of California

Daylight Saving Time is not Associated with an Increased Number of Trauma Activations

UC Irvine
Western Journal of Emergency Medicine: Integrating Emergency 
Care with Population Health
Title
Daylight Saving Time is not Associated with an Increased Number of Trauma Activations
Permalink
https://escholarship.org/uc/item/8jn96248
Journal
Western Journal of Emergency Medicine: Integrating Emergency Care with Population 
Health, 20(4)
ISSN
1936-900X
Authors
Lee, David Chung-Sang
Stahlman, Barbara A.
Sharrah, Mark L.
Publication Date
2019
DOI
10.5811/westjem.2019.5.42780
License
CC BY 4.0
 
Peer reviewed
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University of California
Volume 20, no. 4: July 2019 585 Western Journal of Emergency Medicine
ReseaRch LetteR
 
Daylight Saving Time is not Associated with an Increased 
Number of Trauma Activations
 
David Chung-Sang Lee, MD
Barbara A. Stahlman, MS*
Mark L. Sharrah, MS*
Section Editor: Mark I. Langdorf, MD, MHPE            
Submission history: Submitted Feburary 18, 2019]; Revision received May 23, 2019; Accepted May 29, 2019   
Electronically published July 2, 2019   
Full text available through open access at http://escholarship.org/uc/uciem_westjem    
DOI: 10.5811/westjem.2019.5.42780
[West J Emerg Med. 2019;20(4)585-586.]
INTRODUCTION
Prior studies have reported that during the period of Daylight 
Saving Time (DST) adjustment, there are a greater number of 
motor vehicle collisions.1-3 These studies noted that the increase 
in collisions occurs mainly on the following Monday after the 
time change. We hypothesize that changes in sleep patterns 
may be one of the reasons for this increase. Although the 
number of fatal accidents increases, it is unclear whether there 
is an increased need for hospital-based trauma services. We 
hypothesized that there may be an increased number of trauma 
activations during DST changes that may indicate a need for 
increased resources.
METHODS
We performed a retrospective chart review at an academic, 
tertiary care hospital identified as a Level 1 trauma center. 
This hospital serves multiple counties and has an emergency 
department annual census of 83,000 patients. There are no other 
trauma centers in the primary county. Data, including dates and 
total number of trauma activations for those respective dates, 
were extracted from the hospital’s trauma registry. We compared 
the number of trauma activations occurring on the Mondays of 
DST change to those occurring on the Mondays one week before 
and one week after the DST changes, over a 20-year span. Mann-
Whitney U tests were employed for all analyses. 
RESULTS
At the start of DST, the median number of trauma activations 
(N = 40) on the Mondays of DST (median = 2, range = 7) did not 
differ significantly (U = 190.5; p = 0.41) from the Mondays one 
week before (median = 2.5, range = 7), nor did it significantly 
differ (U = 184; p = 0.34) from the Mondays one week after 
(median = 2.5, range = 7). Likewise, at the end of DST, the 
median number of total trauma activations for the Mondays of 
DST (median = 2, range = 7) did not differ significantly (U = 167; 
p = 0.19) from the Mondays one week before (median = 3, range 
= 7), nor did it significantly differ (U = 161.5; p = 0.15) from the 
Mondays one week after (median = 2, range = 7).
WellSpan York Hospital, Department of Emergency Medicine, York, Pennsylvania *
DISCUSSION
We did not identify an increase in the number of trauma 
activations associated with DST changes during the study period. 
Our hospital is located in the Mid-Atlantic area of the United 
States and our data might differ from other sites by experiencing 
greater lighting changes during DST. Furthermore, with a 
relatively low sample size of trauma activations per day, there 
may not be enough variability to detect changes associated with 
DST. Although this site provides care to multiple counties with 
the nearest Level 1 trauma center over 20 miles away, we did not 
find a significant increase in activations. Currently, there are no 
indications for increasing trauma services during DST changes at 
our single site.
Median Number 
of Activations Range P
Mondays 1 week before start of DST 2.5 7 0.41
Mondays of start of DST 2.0 7
Mondays 1 week after start of DST 2.5 7 0.34
Mondays 1 week before end of DST 3.0 7 0.19
Mondays at end of DST 2.0 7
Mondays 1 week after end of DST 2.0 7 0.15
Table 1. Trauma activations on Mondays.
Address for Correspondence: David Chung-Sang Lee, MD, Wellspan 
York Hospital, 1001 South George Street, York, PA 17406. Email: 
dlee5@wellspan.org.
Conflicts of Interest: By the WestJEM article submission agreement, 
all authors are required to disclose all affiliations, funding sources 
and financial or management relationships that could be perceived 
as potential sources of bias. No author has professional or financial 
relationships with any companies that are relevant to this study. 
There are no conflicts of interest or sources of funding to declare.
Copyright: © 2019 Lee et al. This is an open access article distributed 
in accordance with the terms of the Creative Commons Attribution (CC 
BY 4.0) License. See: http://creativecommons.org/licenses/by/4.0/
Western Journal of Emergency Medicine 586 Volume 20, no. 4: July 2019
Daylight Saving Time is not Associated with an Increased Number of Trauma Activations Lee et al.
REFERENCES
1. Varughese J, Allen RP. Fatal accidents following changes in daylight 
savings time: the American experience. Sleep Med. 2001;2(1):31-6.
2. Lambe M, Cummings P. The shift to and from daylight savings time 
and motor vehicle crashes. Accid Anal Prev. 2000;32(4):609-11.
3. Carey RN, Sarma KM. Impact of daylight saving time on 
road traffic collision risk: a systematic review. BMJ Open. 
2017;7(6):e014319. 


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Daylight Saving Time is not Associated with an Increased Number of Trauma Activations

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