@article {Harper433, author = {Sam Harper and Adam Palayew}, title = {The annual cannabis holiday and fatal traffic crashes}, volume = {25}, number = {5}, pages = {433--437}, year = {2019}, doi = {10.1136/injuryprev-2018-043068}, publisher = {BMJ Publishing Group Ltd}, abstract = {Background Cannabis use has been linked to impaired driving and fatal accidents. Prior evidence suggests the potential for population-wide effects of the annual cannabis celebration on April 20th ({\textquoteleft}4/20{\textquoteright}), but evidence to date is limited.Methods We used data from the Fatal Analysis Reporting System for the years 1975{\textendash}2016 to estimate the impact of {\textquoteleft}4/20{\textquoteright} on drivers involved in fatal traffic crashes occurring between 16:20 and 23:59 hours in the USA. We compared the effects of 4/20 with those for other major holidays, and evaluated whether the impact of {\textquoteleft}4/20{\textquoteright} had changed in recent years.Results Between 1992 and 2016, {\textquoteleft}4/20{\textquoteright} was associated with an increase in the number of drivers involved in fatal crashes (IRR 1.12, 95\% CI 0.97 to 1.28) relative to control days 1 week before and after, but not when compared with control days 1 and 2 weeks before and after (IRR 1.05, 95\% CI 0.92 to 1.28) or all other days of the year (IRR 0.98, 95\% CI 0.88 to 1.10). Across all years we found little evidence to distinguish excess drivers involved in fatal crashes on 4/20 from routine daily variations.Conclusions There is little evidence to suggest population-wide effects of the annual cannabis holiday on the number of drivers involved in fatal traffic crashes.}, issn = {1353-8047}, URL = {https://injuryprevention.bmj.com/content/25/5/433}, eprint = {https://injuryprevention.bmj.com/content/25/5/433.full.pdf}, journal = {Injury Prevention} }