Reading the Data

setwd("C:/Users/s-das/Syncplicity Folders/SHRP2 Visibility Study (TOG-CTS) (Brad Brimley)/FL_Buffer_5Miles/Test Set removing Holidays+Extreme Weather")

##fl_all <- read.csv("FL_Main_Control1.csv")
##dim(fl_all)
##names(fl_all)
##fl_all_01 <- fl_all[c(6, 67, 136, 123,120, 112,116,117,119,254, 280,155,129, 66,126 , 256, 257, 64, 65, 125, 106,
##56, 46, 47, 75, 281)]
##names(fl_all_01)

##a2 <- fl_all_01[c(11, 14, 15, 2, 4, 5, 6, 13, 21, 26, 12, 8, 9, 1, 3, 10, 15, 18:25, 16, 17)]
##names(a2)

## write.csv(a2, "FL_Selec.csv")

a03 <- read.csv("FL_Selec1.csv")
dim(a03)
## [1] 43274    25
a04 <- a03[!duplicated(a03[,1]),]
dim(a04)
## [1] 13156    25
names(a04)
##  [1] "CRASHNUM1"    "DataType"     "Visibility"   "Severity"    
##  [5] "Vis_Score"    "RCIMAXSPD"    "RCIAADT"      "RCISURFWTH"  
##  [9] "LIGHTCOND"    "SKIDNUMBER"   "MatchID"      "Category"    
## [13] "Category1"    "HIGHESTINJ"   "ID"           "AP_LATITUDE" 
## [17] "AP_LONGITUDE" "CR_LATITUDE"  "CR_LONGITUDE" "WORKZONE"    
## [21] "RCISLDWTH2"   "RCIMEDWDTH"   "FULLNAME"     "RDSURFTYPE"  
## [25] "AGE_DRPED"
a05 <- a04[c(2:10)]
summary(a05)
##     DataType        Visibility        Severity      Vis_Score     
##  Control:6654   Excellent:6654   Fatal    : 110   Min.   : 0.500  
##  Main   :6502   Medium   :5328   Injury   :6032   1st Qu.: 2.250  
##                 Poor     :1174   No Injury:7014   Median :10.000  
##                                                   Mean   : 6.148  
##                                                   3rd Qu.:10.000  
##                                                   Max.   :10.000  
##    RCIMAXSPD        RCIAADT         RCISURFWTH      LIGHTCOND     
##  Min.   :25.00   Min.   :   500   Min.   : 9.00   Min.   : 1.000  
##  1st Qu.:40.00   1st Qu.: 27500   1st Qu.:24.00   1st Qu.: 1.000  
##  Median :45.00   Median : 41500   Median :33.00   Median : 1.000  
##  Mean   :46.08   Mean   : 61907   Mean   :32.24   Mean   : 2.467  
##  3rd Qu.:50.00   3rd Qu.: 62000   3rd Qu.:36.00   3rd Qu.: 4.000  
##  Max.   :70.00   Max.   :304000   Max.   :84.00   Max.   :88.000  
##    SKIDNUMBER   
##  Min.   : 0.00  
##  1st Qu.:33.00  
##  Median :36.00  
##  Mean   :36.55  
##  3rd Qu.:40.00  
##  Max.   :62.00
ftable(DataType~Visibility+Severity , data=a05)
##                      DataType Control Main
## Visibility Severity                       
## Excellent  Fatal                   65    0
##            Injury                3027    0
##            No Injury             3562    0
## Medium     Fatal                    0   33
##            Injury                   0 2428
##            No Injury                0 2867
## Poor       Fatal                    0   12
##            Injury                   0  577
##            No Injury                0  585
library(dplyr)
## 
## Attaching package: 'dplyr'
## The following objects are masked from 'package:stats':
## 
##     filter, lag
## The following objects are masked from 'package:base':
## 
##     intersect, setdiff, setequal, union
aa <- a05 %>%
  group_by(Visibility, Severity) %>%
  summarise (n = n()) %>%
  mutate(freq = n / sum(n))
aa
## Source: local data frame [9 x 4]
## Groups: Visibility [3]
## 
##   Visibility  Severity     n        freq
##       (fctr)    (fctr) (int)       (dbl)
## 1  Excellent     Fatal    65 0.009768560
## 2  Excellent    Injury  3027 0.454914337
## 3  Excellent No Injury  3562 0.535317102
## 4     Medium     Fatal    33 0.006193694
## 5     Medium    Injury  2428 0.455705706
## 6     Medium No Injury  2867 0.538100601
## 7       Poor     Fatal    12 0.010221465
## 8       Poor    Injury   577 0.491482112
## 9       Poor No Injury   585 0.498296422
names(a05)
## [1] "DataType"   "Visibility" "Severity"   "Vis_Score"  "RCIMAXSPD" 
## [6] "RCIAADT"    "RCISURFWTH" "LIGHTCOND"  "SKIDNUMBER"
a06 <- a05[c(2, 3, 5:6, 9, 7)]
names(a06)
## [1] "Visibility" "Severity"   "RCIMAXSPD"  "RCIAADT"    "SKIDNUMBER"
## [6] "RCISURFWTH"

Response Variable= Visibility

### MULTINOM
library(nnet)
test <- multinom(Visibility ~Severity+ RCIMAXSPD+ RCIAADT+ SKIDNUMBER+ RCISURFWTH,  data = a05)
## # weights:  24 (14 variable)
## initial  value 14453.343270 
## iter  10 value 12538.175524
## iter  20 value 12160.243304
## final  value 12160.242548 
## converged
summary(test)
## Call:
## multinom(formula = Visibility ~ Severity + RCIMAXSPD + RCIAADT + 
##     SKIDNUMBER + RCISURFWTH, data = a05)
## 
## Coefficients:
##        (Intercept) SeverityInjury SeverityNo Injury   RCIMAXSPD
## Medium  -0.9871889     0.48917664         0.4983746 0.012534852
## Poor    -2.3374533     0.03366072        -0.1039777 0.006956064
##              RCIAADT   SKIDNUMBER   RCISURFWTH
## Medium -1.672057e-07 -0.005188727 -0.003221014
## Poor   -1.771266e-06  0.005486080  0.007046785
## 
## Std. Errors:
##         (Intercept) SeverityInjury SeverityNo Injury    RCIMAXSPD
## Medium 7.132128e-06   3.304684e-06      3.775045e-06 0.0002943583
## Poor   1.212562e-05   6.091315e-06      5.887973e-06 0.0004992284
##             RCIAADT   SKIDNUMBER   RCISURFWTH
## Medium 3.406609e-07 0.0002742943 0.0001726231
## Poor   6.037767e-07 0.0004717143 0.0002990539
## 
## Residual Deviance: 24320.49 
## AIC: 24348.49
library(MASS)
## 
## Attaching package: 'MASS'
## The following object is masked from 'package:dplyr':
## 
##     select
m <- polr(Visibility ~Severity+ RCIMAXSPD+ RCIAADT+ SKIDNUMBER+ RCISURFWTH, 
data = a05, Hess=TRUE)

newdat <- cbind(a06, predict(m, a06[c(2:6)], type = "probs"))
head(newdat)
##    Visibility  Severity RCIMAXSPD RCIAADT SKIDNUMBER RCISURFWTH Excellent
## 1   Excellent No Injury        30   11900         44         22 0.5443798
## 3   Excellent No Injury        35   34000         36         19 0.5325164
## 5   Excellent    Injury        30   21000         44         44 0.5359791
## 9   Excellent    Injury        45   22500         33         24 0.4958473
## 11  Excellent No Injury        45   22500         33         24 0.5047310
## 15  Excellent    Injury        45   19100         45         36 0.4997306
##       Medium       Poor
## 1  0.3784140 0.07720612
## 3  0.3868070 0.08067665
## 5  0.3843704 0.07965052
## 9  0.4118911 0.09226161
## 11 0.4059407 0.08932830
## 15 0.4093005 0.09096888
library(reshape2)
lnewdat <- melt(newdat, id.vars = c("Visibility", "Severity", "RCIMAXSPD", "RCIAADT", "SKIDNUMBER", "RCISURFWTH"),
  variable.name = "Level", value.name="Probability")
head(lnewdat)
##   Visibility  Severity RCIMAXSPD RCIAADT SKIDNUMBER RCISURFWTH     Level
## 1  Excellent No Injury        30   11900         44         22 Excellent
## 2  Excellent No Injury        35   34000         36         19 Excellent
## 3  Excellent    Injury        30   21000         44         44 Excellent
## 4  Excellent    Injury        45   22500         33         24 Excellent
## 5  Excellent No Injury        45   22500         33         24 Excellent
## 6  Excellent    Injury        45   19100         45         36 Excellent
##   Probability
## 1   0.5443798
## 2   0.5325164
## 3   0.5359791
## 4   0.4958473
## 5   0.5047310
## 6   0.4997306
library(ggplot2)
ggplot(lnewdat, aes(x = RCIMAXSPD, y = Probability, colour = Level)) +
  geom_point(alpha = 1/10, size=1) + facet_grid(Visibility ~ Severity, labeller="label_both")+
  aes(colour = Level) + stat_summary(fun.y = mean, geom="line")+theme_bw()

ggplot(lnewdat, aes(x = RCIAADT, y = Probability, colour = Level)) +
  geom_point(alpha = 1/10, size=1) + facet_grid(Visibility ~ Severity, labeller="label_both")+
  aes(colour = Level) + stat_summary(fun.y = mean, geom="line")+theme_bw()

ggplot(lnewdat, aes(x = RCISURFWTH, y = Probability, colour = Level)) +
  geom_point(alpha = 1/10, size=1) + facet_grid(Visibility ~ Severity, labeller="label_both")+
  aes(colour = Level) + stat_summary(fun.y = mean, geom="line")+theme_bw()

ggplot(lnewdat, aes(x = SKIDNUMBER, y = Probability, colour = Level)) +
  geom_point(alpha = 1/10, size=1) + facet_grid(Visibility ~ Severity, labeller="label_both")+
  aes(colour = Level) + stat_summary(fun.y = mean, geom="line")+theme_bw()

Response Variable= Severity

### MULTINOM
library(nnet)
test <- multinom(Severity ~Visibility+ RCIMAXSPD+ RCIAADT+ SKIDNUMBER+ RCISURFWTH,  data = a05)
## # weights:  24 (14 variable)
## initial  value 14453.343270 
## iter  10 value 10397.269273
## iter  20 value 9590.032134
## final  value 9588.350048 
## converged
summary(test)
## Call:
## multinom(formula = Severity ~ Visibility + RCIMAXSPD + RCIAADT + 
##     SKIDNUMBER + RCISURFWTH, data = a05)
## 
## Coefficients:
##           (Intercept) VisibilityMedium VisibilityPoor   RCIMAXSPD
## Injury       2.896103        0.4770137     0.03917657 -0.02672621
## No Injury    4.268856        0.4861324    -0.09860219 -0.04115792
##                RCIAADT SKIDNUMBER   RCISURFWTH
## Injury    7.692452e-06 0.05171408 -0.003089616
## No Injury 1.048614e-05 0.03958956 -0.011693828
## 
## Std. Errors:
##           (Intercept) VisibilityMedium VisibilityPoor    RCIMAXSPD
## Injury    3.39709e-06     1.345086e-06   3.169906e-07 0.0001400554
## No Injury 3.40056e-06     1.346232e-06   3.169006e-07 0.0001401717
##                RCIAADT   SKIDNUMBER   RCISURFWTH
## Injury    1.406955e-06 0.0001312772 8.270150e-05
## No Injury 1.405715e-06 0.0001313758 8.277304e-05
## 
## Residual Deviance: 19176.7 
## AIC: 19204.7
library(MASS)
m <- polr(Severity ~Visibility+ RCIMAXSPD+ RCIAADT+ SKIDNUMBER+ RCISURFWTH,  data = a05, Hess=TRUE)
m
## Call:
## polr(formula = Severity ~ Visibility + RCIMAXSPD + RCIAADT + 
##     SKIDNUMBER + RCISURFWTH, data = a05, Hess = TRUE)
## 
## Coefficients:
## VisibilityMedium   VisibilityPoor        RCIMAXSPD          RCIAADT 
##     2.411532e-02    -1.361726e-01    -1.543723e-02     3.027336e-06 
##       SKIDNUMBER       RCISURFWTH 
##    -9.664274e-03    -8.566029e-03 
## 
## Intercepts:
##     Fatal|Injury Injury|No Injury 
##        -5.943349        -1.289152 
## 
## Residual Deviance: 19207.10 
## AIC: 19223.10
a06 <- a05[c(3, 2, 5:6, 9, 7)]
names(a06)
## [1] "Severity"   "Visibility" "RCIMAXSPD"  "RCIAADT"    "SKIDNUMBER"
## [6] "RCISURFWTH"
newdat <- cbind(a06, predict(m, a06[c(2:6)], type = "probs"))
head(newdat)
##     Severity Visibility RCIMAXSPD RCIAADT SKIDNUMBER RCISURFWTH
## 1  No Injury  Excellent        30   11900         44         22
## 3  No Injury  Excellent        35   34000         36         19
## 5     Injury  Excellent        30   21000         44         44
## 9     Injury  Excellent        45   22500         33         24
## 11 No Injury  Excellent        45   22500         33         24
## 15    Injury  Excellent        45   19100         45         36
##          Fatal    Injury No Injury
## 1  0.007372659 0.4308496 0.5617777
## 3  0.006724122 0.4088157 0.5844602
## 5  0.008648588 0.4694963 0.5218551
## 9  0.008225284 0.4573079 0.5344669
## 11 0.008225284 0.4573079 0.5344669
## 15 0.010320728 0.5124061 0.4772731
library(reshape2)
lnewdat <- melt(newdat, id.vars = c("Severity", "Visibility", "RCIMAXSPD", "RCIAADT", "SKIDNUMBER", "RCISURFWTH"),
  variable.name = "Level", value.name="Probability")
head(lnewdat)
##    Severity Visibility RCIMAXSPD RCIAADT SKIDNUMBER RCISURFWTH Level
## 1 No Injury  Excellent        30   11900         44         22 Fatal
## 2 No Injury  Excellent        35   34000         36         19 Fatal
## 3    Injury  Excellent        30   21000         44         44 Fatal
## 4    Injury  Excellent        45   22500         33         24 Fatal
## 5 No Injury  Excellent        45   22500         33         24 Fatal
## 6    Injury  Excellent        45   19100         45         36 Fatal
##   Probability
## 1 0.007372659
## 2 0.006724122
## 3 0.008648588
## 4 0.008225284
## 5 0.008225284
## 6 0.010320728
library(ggplot2)
ggplot(lnewdat, aes(x = RCIMAXSPD, y = Probability, colour = Level)) +
  geom_point(alpha = 1/10, size=1) + facet_grid(Severity~ Visibility, labeller="label_both")+
  aes(colour = Level) + stat_summary(fun.y = mean, geom="line")+theme_bw()

ggplot(lnewdat, aes(x = RCIAADT, y = Probability, colour = Level)) +
  geom_point(alpha = 1/10, size=1) + facet_grid(Severity~ Visibility, labeller="label_both")+
  aes(colour = Level) + stat_summary(fun.y = mean, geom="line")+theme_bw()

ggplot(lnewdat, aes(x = RCISURFWTH, y = Probability, colour = Level)) +
  geom_point(alpha = 1/10, size=1) + facet_grid(Visibility ~ Severity, labeller="label_both")+
  aes(colour = Level) + stat_summary(fun.y = mean, geom="line")+theme_bw()

ggplot(lnewdat, aes(x = SKIDNUMBER, y = Probability, colour = Level)) +
  geom_point(alpha = 1/10, size=1) + facet_grid(Visibility ~ Severity, labeller="label_both")+
  aes(colour = Level) + stat_summary(fun.y = mean, geom="line")+theme_bw()

######## VGAM
library(VGAM)
## Warning: package 'VGAM' was built under R version 3.2.5
## Loading required package: stats4
## Loading required package: splines
mod2 <- vglm(Severity ~Visibility+ RCIMAXSPD+ RCIAADT+ SKIDNUMBER+ RCISURFWTH,  data = a05,
                         family = multinomial(refLevel = "Fatal"))
summary(mod2)
## 
## Call:
## vglm(formula = Severity ~ Visibility + RCIMAXSPD + RCIAADT + 
##     SKIDNUMBER + RCISURFWTH, family = multinomial(refLevel = "Fatal"), 
##     data = a05)
## 
## Pearson residuals:
##                       Min      1Q Median     3Q   Max
## log(mu[,2]/mu[,1]) -15.06 -0.6006 -0.545 0.8228 1.303
## log(mu[,3]/mu[,1]) -15.19 -0.6929  0.635 0.7133 0.985
## 
## Coefficients:
##                      Estimate Std. Error z value Pr(>|z|)    
## (Intercept):1       2.896e+00  7.212e-01   4.016 5.93e-05 ***
## (Intercept):2       4.269e+00  7.185e-01   5.941 2.83e-09 ***
## VisibilityMedium:1  4.773e-01  2.161e-01   2.209 0.027193 *  
## VisibilityMedium:2  4.864e-01  2.159e-01   2.253 0.024229 *  
## VisibilityPoor:1    4.019e-02  3.183e-01   0.126 0.899517    
## VisibilityPoor:2   -9.759e-02  3.182e-01  -0.307 0.759107    
## RCIMAXSPD:1        -2.674e-02  1.101e-02  -2.429 0.015161 *  
## RCIMAXSPD:2        -4.118e-02  1.101e-02  -3.740 0.000184 ***
## RCIAADT:1           7.692e-06  3.239e-06   2.375 0.017561 *  
## RCIAADT:2           1.049e-05  3.237e-06   3.240 0.001196 ** 
## SKIDNUMBER:1        5.172e-02  1.108e-02   4.667 3.06e-06 ***
## SKIDNUMBER:2        3.960e-02  1.100e-02   3.601 0.000317 ***
## RCISURFWTH:1       -3.072e-03  1.368e-02  -0.225 0.822330    
## RCISURFWTH:2       -1.168e-02  1.367e-02  -0.854 0.392953    
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## Number of linear predictors:  2 
## 
## Names of linear predictors: log(mu[,2]/mu[,1]), log(mu[,3]/mu[,1])
## 
## Dispersion Parameter for multinomial family:   1
## 
## Residual deviance: 19176.7 on 26298 degrees of freedom
## 
## Log-likelihood: -9588.35 on 26298 degrees of freedom
## 
## Number of iterations: 8 
## 
## Reference group is level  1  of the response
exp(VGAM::coef(mod2))
##      (Intercept):1      (Intercept):2 VisibilityMedium:1 
##         18.1023313         71.4334729          1.6117614 
## VisibilityMedium:2   VisibilityPoor:1   VisibilityPoor:2 
##          1.6265306          1.0410134          0.9070251 
##        RCIMAXSPD:1        RCIMAXSPD:2          RCIAADT:1 
##          0.9736101          0.9596603          1.0000077 
##          RCIAADT:2       SKIDNUMBER:1       SKIDNUMBER:2 
##          1.0000105          1.0530820          1.0403915 
##       RCISURFWTH:1       RCISURFWTH:2 
##          0.9969332          0.9883923
mod3 <- vglm(Visibility ~Severity+ RCIMAXSPD+ RCIAADT+ SKIDNUMBER+ RCISURFWTH,  data = a05,
                         family = multinomial(refLevel = "Excellent"))
summary(mod3)
## 
## Call:
## vglm(formula = Visibility ~ Severity + RCIMAXSPD + RCIAADT + 
##     SKIDNUMBER + RCISURFWTH, family = multinomial(refLevel = "Excellent"), 
##     data = a05)
## 
## Pearson residuals:
##                       Min      1Q  Median      3Q   Max
## log(mu[,2]/mu[,1]) -1.121 -0.8666 -0.7705  1.1958 1.769
## log(mu[,3]/mu[,1]) -0.548 -0.4607 -0.4166 -0.1121 3.780
## 
## Coefficients:
##                       Estimate Std. Error z value Pr(>|z|)    
## (Intercept):1       -9.872e-01  2.693e-01  -3.666 0.000246 ***
## (Intercept):2       -2.338e+00  4.272e-01  -5.472 4.44e-08 ***
## SeverityInjury:1     4.891e-01  2.161e-01   2.263 0.023611 *  
## SeverityInjury:2     3.387e-02  3.180e-01   0.107 0.915155    
## SeverityNo Injury:1  4.983e-01  2.159e-01   2.309 0.020967 *  
## SeverityNo Injury:2 -1.038e-01  3.179e-01  -0.327 0.744014    
## RCIMAXSPD:1          1.254e-02  2.407e-03   5.208 1.91e-07 ***
## RCIMAXSPD:2          6.955e-03  4.176e-03   1.665 0.095865 .  
## RCIAADT:1           -1.673e-07  5.422e-07  -0.308 0.757702    
## RCIAADT:2           -1.770e-06  9.482e-07  -1.867 0.061883 .  
## SKIDNUMBER:1        -5.188e-03  3.146e-03  -1.649 0.099110 .  
## SKIDNUMBER:2         5.485e-03  5.556e-03   0.987 0.323469    
## RCISURFWTH:1        -3.220e-03  2.592e-03  -1.242 0.214159    
## RCISURFWTH:2         7.045e-03  4.406e-03   1.599 0.109821    
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## Number of linear predictors:  2 
## 
## Names of linear predictors: log(mu[,2]/mu[,1]), log(mu[,3]/mu[,1])
## 
## Dispersion Parameter for multinomial family:   1
## 
## Residual deviance: 24320.49 on 26298 degrees of freedom
## 
## Log-likelihood: -12160.24 on 26298 degrees of freedom
## 
## Number of iterations: 5 
## 
## Reference group is level  1  of the response
exp(VGAM::coef(mod3))
##       (Intercept):1       (Intercept):2    SeverityInjury:1 
##          0.37261658          0.09656466          1.63092452 
##    SeverityInjury:2 SeverityNo Injury:1 SeverityNo Injury:2 
##          1.03445483          1.64598480          0.90140100 
##         RCIMAXSPD:1         RCIMAXSPD:2           RCIAADT:1 
##          1.01261417          1.00697878          0.99999983 
##           RCIAADT:2        SKIDNUMBER:1        SKIDNUMBER:2 
##          0.99999823          0.99482508          1.00550040 
##        RCISURFWTH:1        RCISURFWTH:2 
##          0.99678481          1.00706952
mod4 <- vglm(Visibility ~Severity+ RCIMAXSPD+ RCIAADT+ SKIDNUMBER+ RCISURFWTH,  data = a05,
                         family = multinomial(refLevel = "Poor"))
summary(mod4)
## 
## Call:
## vglm(formula = Visibility ~ Severity + RCIMAXSPD + RCIAADT + 
##     SKIDNUMBER + RCISURFWTH, family = multinomial(refLevel = "Poor"), 
##     data = a05)
## 
## Pearson residuals:
##                       Min      1Q  Median     3Q   Max
## log(mu[,1]/mu[,3]) -2.711 -0.5879  0.7928 0.8662 1.074
## log(mu[,2]/mu[,3]) -2.719 -0.4711 -0.4404 1.0518 1.603
## 
## Coefficients:
##                       Estimate Std. Error z value Pr(>|z|)    
## (Intercept):1        2.338e+00  4.272e-01   5.472 4.44e-08 ***
## (Intercept):2        1.350e+00  4.472e-01   3.020  0.00253 ** 
## SeverityInjury:1    -3.387e-02  3.180e-01  -0.107  0.91515    
## SeverityInjury:2     4.553e-01  3.410e-01   1.335  0.18180    
## SeverityNo Injury:1  1.038e-01  3.179e-01   0.327  0.74401    
## SeverityNo Injury:2  6.021e-01  3.409e-01   1.766  0.07733 .  
## RCIMAXSPD:1         -6.955e-03  4.176e-03  -1.665  0.09587 .  
## RCIMAXSPD:2          5.581e-03  4.220e-03   1.322  0.18601    
## RCIAADT:1            1.770e-06  9.482e-07   1.867  0.06188 .  
## RCIAADT:2            1.603e-06  9.625e-07   1.666  0.09579 .  
## SKIDNUMBER:1        -5.485e-03  5.556e-03  -0.987  0.32347    
## SKIDNUMBER:2        -1.067e-02  5.646e-03  -1.890  0.05870 .  
## RCISURFWTH:1        -7.045e-03  4.406e-03  -1.599  0.10982    
## RCISURFWTH:2        -1.027e-02  4.495e-03  -2.283  0.02241 *  
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## Number of linear predictors:  2 
## 
## Names of linear predictors: log(mu[,1]/mu[,3]), log(mu[,2]/mu[,3])
## 
## Dispersion Parameter for multinomial family:   1
## 
## Residual deviance: 24320.49 on 26298 degrees of freedom
## 
## Log-likelihood: -12160.24 on 26298 degrees of freedom
## 
## Number of iterations: 5 
## 
## Reference group is level  3  of the response
exp(VGAM::coef(mod4))
##       (Intercept):1       (Intercept):2    SeverityInjury:1 
##          10.3557549           3.8587260           0.9666928 
##    SeverityInjury:2 SeverityNo Injury:1 SeverityNo Injury:2 
##           1.5766029           1.1093842           1.8260295 
##         RCIMAXSPD:1         RCIMAXSPD:2           RCIAADT:1 
##           0.9930696           1.0055963           1.0000018 
##           RCIAADT:2        SKIDNUMBER:1        SKIDNUMBER:2 
##           1.0000016           0.9945297           0.9893831 
##        RCISURFWTH:1        RCISURFWTH:2 
##           0.9929801           0.9897875