What is happening isn't just ONE thing. The heat from the asphalt is reflecting on your trees causing the bark to thaw prematurely. Usually ugly but not a deal breaker. The thawed portion of the trunk might have killed the vascular system beneath the bark but not the entire circumference.
Your trees are surrounded by grass right up to the bark. This is a big deal to the health of your trees. Look at the first picture where you are able to see the extent of water being held to the bottom of your tree. This doesn't cause death right away but it allows bacteria to begin compromising the bark and vascular system...this does kill a tree and causes them to become weakened and susceptible to wind damage and then insect damage. And kids are just attracted to peeling bark. They aren't doing any damage past what has already happened.
The vascular system just below the bark is the critical part to your entire tree. A tree can survive just fine when only a part of the vascular system is compromised (scratch the surface below the bark and you will see green...this is the top of the vascular system and it is only less than an eighth of an inch thick).
Remove that grass at least 2' radius from the trunk, get rid of all mulch touching the bark as well. Just the roots should be below the surface and pull soil, mulch, rock, grass away from the bark that should be above the surface to be kept dry by wind, air, and the bark's own chemistry. You might just get rid of ALL grass around those trees. Mowing and trimming are another danger to the bark of your trees. Get rid of any staking. Staking only makes the trunk and root support systems weaker. Right now you want movement by the wind which causes your trunks and roots to get larger and stronger. Have you ever had a limb of your own in a cast for a few months? That is what happens when a tree is staked.
Please post a picture of the entire group of trees. What have you added, such as fertilizer. How do you water? Who planted these trees, the HOA? Who mows and trims the grass around these trees. Have you had an arborist diagnose these? 5 trees is an investment and if one has broken off this is a good wake up call to save the others. How about pruning?
To alleviate the difference in temperature painting the bark on the street side or south side in WHITE will mitigate the difference in temperature. They do this in orchards...the only time trunks are ever messed with. I'd wait until you hire an arborist (the HOA if involved should pay for this) and/or send us pictures of the entire tree (s).