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)Israel1994–1996SleepXAll 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)USA1987–2006SleepXAll 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)Canada1991–1992SleepXAll 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 lightXAll collisionsMonday before and afterSpring and autumn: no statistically significant short-term effects of DST
Green30 (1980)UK1975–1977LightEvening 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)USA1976–1978SleepXAll 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 lightAll 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)Finland1981–2006SleepXAll 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)Sweden1984–1995SleepXAll 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)USA1973–1974LightAll 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 lightAll 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)USA1998–2000LightFatal 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)USA1975–1995SleepXAll 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)UK1983–1993LightCasualties: 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.