Its appalling that things like this occer, but in a war zone sad events such as this are always going to happen :(. I can understand why a family might want to avoid contact with American soldiers after Abu Ghraib and all that, but then I can also understand the itchy trigger fingers of Americans manning roadblocks after seeing their comrades fall victim to car bombs driven at their checkpoints. I notice the quickness to condemn the conduct of the American soldiers, and indeed I believe there are measures to prevent cars running roadblocks and reduce the risk to the soldiers which should be taken wherever possible. Caltrops which basically act like a stinger to deflate the car tyres, and/or concrete barricades. The problem is, faced with suicide bombers rather than people just trying to get through, by the time its clear the vehicle isn't going to stop its already close enough to do some damage. I recall the British army using the 'tethered goat' technique, of parking one of their armoured vehicles about 100 yards up from the real checkpoint, and putting all the usual barricades and that around it. Any suicide bomber driving into the checkpoint ends up blowing up an empty vehicle (driving at speed they'd generally not be sure until up close whether the first part of the checkpoint is manned, by which time it'd be obvious to the soldiers further down the road that they'd try to run/attack the checkpoint by which time they can react more quickly to deal with any threat), The situation on the ground though is so unpredictable that no measures taken to prevent such incidents are foolproof - furthermore, many are impractical due to a lack of resources. A small squad of infantry ordered to set up a checkpoint at short notice has neither the time nor equipment to use the techniques mentioned above, whether or not they have the inclination to (and I think you'd struggle to find soldiers who actually like to shoot at a car with children inside). Northern Ireland showed the inherent risks of jumpy soldiers manning checkpoints on civilian roads - the infamous case of the soldier shooting someone (fearing they were under fire from the IRA) after their car backfired upon approaching a roadblock springs to mind.