Fatal motor vehicle collisions and associated deaths from 2007 to 2018 in United States jurisdictions with legalized recreational cannabis, comparing the first 12 months to subsequent months
| Event | No. of events | Person-years of observation | Rate per 100 000 person-years (95% CI) | IRR (95% CI) | |
|---|---|---|---|---|---|
| Crude | Adjusted* | ||||
| Recreational cannabis legalization | |||||
| Fatal motor vehicle collision | 73 982 | 924 545 813 | 8.00 (7.94–8.06) | ||
| No legalization | 68 180 | 855 020 030.8 | 7.92 (7.86–7.99) | 1.00 (reference) | 1.00 (reference) |
| First 12 mo after legalization† | 5802 | 69 525 782.3 | 8.35 (8.13–8.56) | 1.01 (0.93–1.11) | 1.12 (1.01–1.23) |
| Subsequent months after legalization‡ | 11 314 | 137 458 217.3 | 8.23 (8.08–8.38) | 1.06 (1.00–1.13) | 1.22 (1.11–1.35) |
| First 12 mo v. subsequent months‡ | – | – | – | 0.96 (0.88–1.05) | 0.92 (0.84–1.02) |
| Death from motor vehicle collision | 80 402 | 924 545 813 | 8.70 (8.64–8.76) | – | |
| No legalization | 61 822 | 717 561 813.4 | 8.62 (8.55–8.68) | 1.00 (reference) | 1.00 (reference) |
| First 12 mo after legalization† | 6290 | 69 525 782.3 | 9.05 (8.83–9.27) | 1.00 (0.92–1.10) | 1.11 (1.00–1.24) |
| Subsequent months after legalization‡ | 12 290 | 137 458 217.3 | 8.94 (8.78–9.10) | 1.06 (1.00–1.12) | 1.23 (1.11–1.37) |
| First 12 mo v. subsequent months‡ | – | – | – | 0.96 (0.89–1.04) | 0.92 (0.84–1.01) |
| Opening of recreational cannabis dispensaries | |||||
| Fatal motor vehicle collision | 60 518 | 774 128 598 | 7.82 (7.76–7.88) | ||
| No open dispensaries | 50 275 | 653 841 729.2 | 7.69 (7.62–7.76) | 1.00 (reference) | 1.00 (reference) |
| First 12 mo of open dispensaries† | 4968 | 60 437 733.9 | 8.22 (7.99–8.45) | 1.03 (0.95–1.13) | 1.13 (1.03–1.24) |
| Subsequent months of open dispensaries‡ | 5275 | 59 849 134.9 | 8.81 (8.58–9.05) | 1.13 (1.08–1.18) | 1.34 (1.24–1.46) |
| First 12 mo v. subsequent months‡ | – | – | – | 0.92 (0.82–1.04) | 0.88 (0.76–1.02) |
| Death from motor vehicle collision | 65 835 | 774 128 598 | 8.50 (8.44–8.57) | ||
| No open dispensaries | 54 685 | 653 841 729.2 | 8.36 (8.29–8.43) | 1.00 (reference) | 1.00 (reference) |
| First 12 mo of open dispensaries† | 5426 | 60 437 733.9 | 8.98 (8.74–9.22) | 1.03 (0.95–1.13) | 1.13 (1.03–1.25) |
| Subsequent months of open dispensaries§ | 5724 | 59 849 134.9 | 9.56 (9.32–9.82) | 1.12 (1.07–1.17) | 1.35 (1.25–1.45) |
| First 12 mo v. subsequent months§ | – | – | – | 0.92 (0.82–1.03) | 0.88 (0.76–1.01) |
Note: CI = confidence interval, IRR = incidence rate ratio.
↵* Adjusted for calendar year, modelled as a continuous variable.
↵† Includes up to 12 months for each jurisdiction (some jurisdictions contributed less than 12 mo, depending on their dates of legalization or opening of dispensaries).
↵‡ Excludes Michigan and Vermont (no subsequent months of legalization available).
↵§ Excludes California and Massachusetts (no subsequent months of open dispensaries available).