Independent Variables

OLS Multiple Linear Regression

Ridge Regression

Coeff. Estimate

t-Statistics

P-value

Coeff. Estimate

t-statistics

P-value

Intercept

0.4493

0.000

0.1417

0.000

Rd_char

1) Straight

2) U. grade

3) D. grade

4) H. Curve

0.202

0.471

3.319

2.772

0.393

6.794

1.614

2.637

0.149

0.222

0.125

0.216

0.193

0.513

2.561

3.389

0.317

4.312

4.729

9.476

0.044

0.001

0.001

0.002

Rd_surf

1) Dry

2) Wet

3) Muddy

−0.482

2.322

1.782

0.263

4.866

11.412

0.243

0.323

0.193

−1.172

1.778

1.914

1.489

2.533

8.612

0.041

0.002

0.001

Weather

1) Clear

2) Rain

3) Snow

4) Fog

−0.541

6.439

3.743

5.016

0.482

6.748

6.188

14.871

0.175

0.133

0.202

0.382

1.398

2.773

4.493

8.144

−1.627

9.163

8.961

7.643

0.031

0.003

0.001

0.002

Light

1) Day Light

2) Light ON

3) No Light

2.016

3.153

4.095

1.179

3.244

11.877

0.092

0.082

0.076

0.199

2.371

5.876

2.191

5.333

14.742

0.007

0.044

0.001

Drv_age

1) <21 yr.

2) (21 to 65)

3) >65 yr.

3.289

−0.541

3.177

11.853

1.096

11.847

0.004

0.139

0.102

4.479

−0.354

7.618

17.248

1.435

11.987

0.001

0.003

0.002

Drv_sex

1) Male

2) Female

−3.337

−5.228

13.449

12.767

0.131

0.067

−1.899

−2.993

11.169

14.119

0.002

0.002

Vehtype

1) P. Car

2) Van

3) Bus

4) Truck

−5.301

−2.699

5.890

2.969

14.285

13.312

12.449

8.771

0.139

0.129

0.102

0.202

−5.612

−3.411

4.712

5.844

16.339

10.417

8.746

9.352

0.044

0.022

0.003

0.002

AADT

6.974

3.683

0.122

4.811

6.213

0.023