Item

Testing Data

Poisson Regression Model

Testing Data

Negative Binomial Model

Variables

Coeff. Estimate

Wald Chi Square Statistics

P-value

Coeff. Estimate

Wald Chi Square Statistics

P-value

Intercept

−2.681

21.088

0.000

−2.323

22.709

0.000

Rd_char

1―Straight

−0.109

0.343

0.046

−0.193

0.371

0.044

2―U.grade

0.332

7.774

0.002

0.412

6.311

0.001

3―D.grade

1.389

4.614

0.002

1.559

3.727

0.001

4―H. Curve

1.703

6.633

0.002

1.388

5.476

0.001

Rdsurf

1―Dry

−0.282

0.225

0.043

−0.172

0.482

0.041

2―Wet

1.321

5.867

0.003

1.478

5.533

0.002

3―Muddy

0.732

10.448

0.001

0.915

9.611

0.001

Weather

1―Clear

−0.221

0.411

0.077

−0.393

0.622

0.079

2―Rain

−1.032

4.747

0.033

−1.703

7.153

0.003

3―Snow

1.744

7.182

0.002

2.433

7.911

0.001

4―Fog

2.011

12.877

0.000

3.044

9.633

0.000

Light

1―Day Light

−0.019

0.177

0.092

0.099

−0.191

0.107

2―Light ON

−0.153

0.242

0.041

0.331

−0.338

0.044

3―No Light

2.091

12.944

0.001

3.866

12.852

0.000

Drv_age

1―< 21 yr.

2.281

13.553

0.001

4.472

12.264

0.001

2―(21 to 65)

−0.141

0.093

0.032

−0.394

0.435

0.003

3―> 65 yr.

2.176

13.844

0.001

5.611

12.919

0.001

Drv_sex

1―Male

−1.337

15.445

0.031

−1.499

12.069

0.002

2―Female

−1.228

14.688

0.027

−2.093

13.419

0.001

Vehtype

1―P. Car

−2.301

17.285

0.036

−4.612

18.333

0.041

2―Van

−2.099

12.312

0.021

−2.411

12.419

0.023

3―Bus

1.890

10.449

0.002

2.712

9.747

0.003

4―Truck

1.909

9.781

0.002

2.644

6.552

0.002

Sec_leng

1―0.2 km

−1.266

2.322

0.023

−2.229

5.471

0.026

2―0.5 km

−1.441

5.888

0.036

−2.741

6.071

0.039

3―0.9 km

−1.155

2.991

0.029

−1.791

5.559

0.033

AADT

2.761

4.663

0.022

2.819

5.113

0.001