Car-bomb attacks are one of the most difficult to defend against.
Once a person has made the decision to become a suicide bomber, he has a clear advantage in that he is not afraid of being checked, but is looking to be checked at a checkpoint in order to maximize his kill.
Like the Japanese kamikaze bombers in World War II, we are now facing an enemy that is fighting the entire Western Civilization and has a significant amount of fearlessness.
This can and must be overcome, but it will take a hardening of our skin.
We need to know our enemy and then we can make a good plan and eventually defeat them before they defeat us.