Table 1

Characteristics of papers included: short-term timeframe

Author (year)CountryYearsFocus (sleep/light)By seasonBy time of day (morning/evening)Population and outcomeTimeframeFinding (narrative)
Askenasey26 (1997)Israel1994–1996Sleep✓XAll collisions2 weeks before and 2 weeks afterSpring: technically a significant increase in RTCs after change to DST— however, 'within the chain of day-to-day increases the alleged effect of DST became non-significant'
Autumn: significant decrease in RTCs after change back to ST (attributed to sleep benefits)
Conte27 (2007)USA1987–2006Sleep✓XAll collisions excluding pedestrians2 weeks before and 2 weeks afterSignificant differences in mean daily RTCs between DST adjusted and DST unadjusted Mondays (DST ‘seems to increase the number of traffic accidents’)
Note: distinction between spring and autumn not clear from inferential statistics reported
Coren28 (1996)Canada1991–1992Sleep✓XAll collisions1 week before, week of and 1 week afterSpring: the spring DST shift resulted in an average increase in RTCs of approximately 8%
Autumn: the autumn shift resulted in a decrease in RTCs of approximately the same magnitude
Crawley29 (2012)USA1976–2010Sleep and light✓XAll collisionsMonday before and afterSpring and autumn: no statistically significant short-term effects of DST
Green30 (1980)UK1975–1977Light✓Evening onlyAll collisions5 days before and after and 10  days before and afterSpring: based on 5-day comparison, reduction of 31% in RTCs in March
Autumn: increase of 64% in October. Less marked findings for 10-day data
Hicks31 (1983)USA1976–1978Sleep✓XAll collisions1 week before and 1 week afterSpring and autumn: regardless of season, DST change was associated with a significant increase in RTCs during the postchange weeks
Hicks25 (1998)USA1989–1992Sleep✓*XAll alcohol-related fatal road traffic collisions1 week before and 1 week afterSpring and autumn: alcohol-related fatalities increased significantly in the first week after the DST transition, although this returned to baseline by the second week
Note: spring and autumn combined as not statistically significantly different
Huang16 (2010)USA2001–2007Sleep and light✓✓All collisions and fatal collisionsFirst day (Sunday) of time change compared with other SundaysSpring: short-term effect is not statistically significant
Autumn: short-term effect is not statistically significant
Lahti32 (2010)Finland1981–2006Sleep✓XAll collisions1 week before and 1 week afterSpring and autumn: transitions into and out of DST did not significantly increase the amount of traffic collisions
Lambe33 (2000)Sweden1984–1995Sleep✓XAll collisionsMonday before and after, and 1 week afterSpring and autumn: the shift to and from DST did not have measurable effects on RTC incidence
Meyerhoff17 (1978)USA1973–1974Light✓✓All fatal collisionsMorning and evening on day of transitions in 1974 (DST) and 1973 (No DST)Spring and autumn: DST reduced fatal RTCs by approximately 1% during several weeks at spring and autumn transitions. This effect was attributed to the spring transition, with little change during the autumn transition
Sarma & Carey20 (2016)Ireland2003–2012Light✓✓
Morning, evening, combined morning and evening, full day		Collisions, injuries, fatalities for different road users (pedestrians, cyclists and all road users)1 and 2 weeks before and after transition into and out of DSTSpring: no change in collisions. Increase in casualties in the mornings in 2-week comparisons (33.5%) and increase in pedestrian casualties (105.3%)
Autumn: decrease in collisions in the morning period at 1-week (26.9% decrease) and 2-week (17.3% decrease) comparisons. Evening pedestrian casualties increased in both sets of analyses (68% higher at 1 week and 32.5% over 2 weeks)
Smith34 (2014)USA2002–2011Sleep and light✓✓All fatal collisionsUnclearSpring: 5.4%–7% increase in fatal RTCs immediately following spring transition. Autumn: no impact in autumn
Sood and Ghosh22 (2007)USA1976–2003Sleep and lightSpring onlyXFatal collisions: pedestrians and motor vehicle occupantsMonday before, Monday of and Monday afterSpring: no short-term effect, having controlled for collision trends within and across years
Stevens35 (2006)USA1998–2000Light✓✓Fatal and non-fatal collisions involving pedestrians and motor vehicle occupantsFive working days before & afterSpring and autumn: the immediate impact of DST, both spring and autumn, is negative, but is particularly marked for the autumn transition. An increase in daylight results in a decrease in the number of pedestrian crashes
Varughese36 (2001)USA1975–1995Sleep✓XAll fatal collisionsSaturday/Sunday and Monday of the transition vs same days for the week before and afterSpring: there was a small significant increase in fatal RTCs on Monday from 78.2 to 83.5 (no impact on Saturday or Sunday).
Autumn: there was a significant increase found in fatalities for Sunday from 126.4 to 139.5 (no difference for Saturday or Monday)
Whittaker19 (1996)UK1983–1993Light✓✓Casualties: vehicle occupants, cyclists, pedestrians, children1  week before and 1 week afterOverall net reduction in casualty numbers for BST periods compared with GMT.
Spring: onset of BST in spring associated with reductions in casualty numbers of 6% in morning and 11% in evening. No rise in casualties with the darker mornings. Reductions were maximal in the pedestrian (36%), cyclist (11%) and schoolchild (24%) subgroups
Autumn: the change back to GMT in autumn produced an anticipated reduction (6%) in casualties in the lighter mornings. Darker evenings associated with significant increases in casualties (4%), mainly vehicle (5%) and pedestrian (8%)

  • *Spring and autumn transition data were combined as not statistically different from one another.

  • BST, British Standard Time; DST, daylight saving time; GMT, Greenwich Mean Time; RCT, randomised controlled trial.