He's used to being safe inside where it has a roof and its quiet, outside, it's big and open and cars are big, noisy monsters coming too close to him. Keep socializing him and talk soothingly to him as the cars pass, telling him its ok. Soon, he might never fully get used to is, but he won't be as afraid. Good walking.
__________________ My Sweet Baby Girls Chloe Primrose Pink ** Willow Patchouli Blu  Miss Abigail |