Impact of COVID-19 on MVCs stratified by number of vehicles included in crash, comparison within years 2018–2020
| Outcome models | 2020 | 2019 | 2018 | 2017 | ||||||||
| Step change IRR | Slope change | P value | Step change IRR | Slope change | P value | Step change IRR | Slope change | P value | Step change IRR | Slope change | P value | |
| All type crashes | 1.08 (0.84 to 1.41) | 0.99 (0.99 to 1.00) | 0.52 | 0.91 (0.81 to 1.03) | 1.00 (0.99 to 1.00) | 0.148 | 1.06 (0.86 to 1.29) | 1.01 (1.00 to 1.02) | 0.56 | 0.87 (0.74 to 1.02) | 1.01 (1.00 to 1.02) | 0.09 |
| Single |
2.29
(1.32 to 3.99) | 0.98 (0.97 to 1,00) | <0.01 | 0.77 (0.60 to 0.88) | 0.99 (0.99 to 1.00) | 0.08 | 0.87 (0.54 to 1.34) | 1.01 (1.00 to 1.02) | 0.55 | 1.01 (0.71 to 1.44) | 1.02 (1.01 to 1.04) | 0.95 |
| Multiple |
0.83
(0.71 to 0.95) | 1.00 (0.99 to 1.01) | 0.01 | 0.95 (0.84 to 1.07) | 1.00 (0.99 to 1.00) | 0.43 | 1.11 (0.92 to 1.32) | 1.00 (1.00 to 1.01) | 0.25 |
0.84
(0.73 to 0.97 | 1.00 (1.00 to 1.02) | 0.01 |
| Any injury crash | 1.03 (0.79 to 1.35) | 0.99 (0.98 to 1.00) | 0.79 | 0.98 (0.86 to 1.11) | 1.00 (0.99 to 1.00) | 0.78 | 1.00 (0.83 to 1.22) | 1.00 (1.00 to 1.01) | 0.93 | 0.92 (0.78 to 1.07) | 1.00 (0.99 to 1.01) | 0.29 |
| Single |
1.76
(1.11 to 2.79) | 0.98 (0.98 to 1.00) | 0.02 | 0.95 (0.72 to 1.25) | 0.99 (0.99 to 1.00) | 0.74 | 0.81 (0.61 to 1.07) | 1.01 (1.00 to 1.02) | 0.14 | 1.13 (0.83 to 1.55) | 1.01 (0.99 to 1.02) | 0.42 |
| Multiple |
0.79
(0.63 to 0.98) | 1.00 (0.99 to 1.01) | 0.04 | 0.98 (0.85 to 1.14) | 1.00 (0.99 to 1.01) | 0.87 | 1.08 (0.87 to 1.32) | 1.00 (0.99 to 1.01) | 0.50 | 0.86 (0.74 to 1.01) | 1.00 (0.99 to 1.01) | 0.07 |
| Non-injury crash | 1.10 (0.84 to 1.43) | 0.99 (0.98 to 1.00) | 0.47 | 0.89 (0.79 to 1.01) | 1.00 (0.99 to 1.00) | 0.09 | 1.07 (0.86 to 1.33) | 1.00 (1.00 to 1.01) | 0.49 | 0.85 (0.72 to 1.01) | 1.01 (1.00 to 1.02) | 0.08 |
| Single |
2.55
(1.38 to 4.69) | 0.98 (0.96 to 1.00) | <0.01 |
0.71
(0.51 to 0.99) | 0.99 (0.97 to 1.00) | 0.04 | 0.89 (0.50 to 1.57) | 1.01 (0.99 to 1.02) | 0.69 | 0.96 (0.64 to 1.44) | 1.02 (1.01 to 1.04) | 0.86 |
| Multiple |
0.84
(0.72 to 0.97) | 1.00 (0.99 to 1.00) | 0.01 | 0.94 (0.82 to 1.06) | 1.00 (0.99 to 1.00) | 0.34 | 1.12 (0.93 to 1.34) | 1.00 (1.00 to 1.01) | 0.22 |
0.83
(0.72 to 0.97) | 1.00 (1.00 to 1.01) | 0.02 |
| Fatal crash | 2.17 (0.68 to 6.89) | 1.01 (0.97 to 1.04) | 0.18 | 0.93 (0.29 to 2.93) | 0.99 (0.95 to 1.04) | 0.91 | 0.79 (0.26 to 2.41) | 1.03 (0.99 to 1.06) | 0.69 | 1.37 (0.50 to 3.77) | 1.00 (0.60 to 1.04) | 0.53 |
| Single |
4.10
(1.06 to 15.86) | 1.01 (0.96 to 1.06) | 0.04 | 0.73 (0.16 to 3.32) | 0.99 (0.93 to 1.05) | 0.68 | 1.28 (0.27 to 6.08) | 1.03 (0.98 to 1.08) | 0.75 | 1.67 (0.38 to 7.42) | 0.99 (0.94 to 1.05) | 0.49 |
| Multiple | 0.84 (0.11 to 6.02) | 1.01 (0.95 to 1.08) | 0.86 | 1.22 (0.18 to 7.96) | 1.00 (0.93 to 1.08) | 0.83 | 0.52 (0.12 to 2.25) | 1.02 (0.97 to 1.07) | 0.38 | 1.10 (0.27 to 4.37) | 1.00 (0.95 to 1.06) | 0.887 |
Model specified a Poisson distribution of the outcome with a log transformed VMT as population offset. Robust SEs were specified for a more conservative estimate of coefficients. Models include linear time, average daily precipitation and average daily highest recorded temperature. Years 2019 and 2018 are provided as comparison for 2020 and are thus comparison units of measure. Post-stay-at-home period is 23 March–30 April.
Bold Values note statistical significance <=0.05.
IRR, incidence rate ratio; VMT, vehicle miles travelled.