(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