T.,
Two things:
Your son may have sensitivities - things you wouldn't think possible for a toddler. I'm just getting to the tip of the iceberg for my son. I'm trying to find the site for sensitivities (there is a site with a list that's *huge*). and what you might think is normal may not be, and what you think might not be normal, just might. It doesn't diagnose for you, just gives you leads (like any tool).
Forcing him to do something is not the way to go. If he is afraid of the street (good for his safety) crossing it when he is afraid without comforting him, is not going to get either of you anywhere, and will inevitably, leave him with a feeling of a lack of safety.
Comfort for an infant, toddler, child is such a big thing and I see so many parents (now that I am one!) gloss over it and tell their child 'Oh that's not so bad' or 'oh that didn't hurt!' or 'oh, it's over now, get over it!'
You would do well and go far with your child if you comforted every teary hurt (and as you would an adult) ask if they are hurt (whether they cry or not). Surprisingly enough, even if they are not hurt, they usually DON'T start up the water works as some parents like to say they don't like to precipitate.
I find when I ask my son if he is okay after falling, he does the same for me. he becomes more solicitous through my modeling it.
Good luck,
M.
