Removing zeros
DataTrain$drv_age2[DataTrain$drv_age2==0] <- NA
DataTrain$vh_value[DataTrain$vh_value==0] <- NA
DataTrain$vh_cyl[DataTrain$vh_cyl==0] <- NA
DataTrain$vh_weight[DataTrain$vh_weight==0] <- NA
DataTrain$drv_drv2[DataTrain$drv_drv2==0] <- NA