(a) Safety effectiveness of safety edge treatment with lane widening | ||||||||
Crash Type | Severity | Crashes in after period | CMF for combined treatments | SE | 95% CI | % Reduction | Significance | |
Observed | EB estimate | |||||||
All | All | 29 | 50 | 0.51 | 0.115 | (0.29, 0.74) | 49 | Significant at 95% CI |
Fatal and injury | 7 | 11 | 0.6 | 0.240 | (0.13, 1.07) | 40 | Not significant at 90% CI | |
Lane-departure | All | 24 | 17 | 0.65 | 0.177 | (0.30, 1.00) | 35 | Significant at 90% CI |
Fatal and injury | 3 | 6 | 0.53 | 0.312 | (0, 1.14) | 47 | Not significant at 90% CI | |
(b) Safety effectiveness of adding 2 ft paved shoulders with asphalt resurfacing and/or shoulder rumble strips | ||||||||
Crash Type | Severity | Crashes in after period | CMF for combined treatments | SE | 95% CI | % Reduction | Significance | |
Observed | EB estimate | |||||||
All | All | 655 | 684 | 0.96 | 0.046 | (0.87, 1.05) | 4 | Not significant at 90% CI |
Fatal and injury | 146 | 211 | 0.69 | 0.064 | (0.56, 0.82) | 31 | Significant at 95% CI | |
Lane-departure | All | 187 | 341 | 0.55 | 0.045 | (0.46, 0.64) | 45 | Significant at 95% CI |
Fatal and injury | 75 | 140 | 0.53 | 0.067 | (0.40, 0.66) | 47 | Significant at 95% CI |