(a) Model 1

Treatments

All crash type

Lane-departure crashes

All

Fatal and injury

All

Fatal and injury

Safety edge

0.784

0.770

0.858

0.758

1 ft lane widening

1.098

1.333

1.242

1.351

2 ft lane widening

1.205

1.778

1.542

1.825

(b) Model 2

Treatments

All crash type

Lane-departure crashes

All

Fatal and Injury

All

Fatal and Injury

Asphalt resurfacing

0.399

0.388

1.267

1.360

Adding 2 ft paved shoulders with shoulder rumble strips

0.745

0.516

0.766

0.536

Adding 2 ft paved shoulders

1.292

1.107

0.727

0.731