The Taliban believed that the roadside bomb (IED, or Improvised Explosive Device) was the key to victory in Afghanistan, and a wonder weapon that would succeed where other ideas had failed. This is unlikely, but this is what Taliban commanders have been telling their subordinates for the last few years. As a result, the ineffectiveness of the bombs last year is believed to be a major blow to Taliban morale.
The Taliban learned the strategy of relying on the IED without having the resources (money, explosives, and skilled bomb makers) to replicate what the Iraqi insurgents could, and without learning the lesson that even the better Sunni Arab (and Shia Sadrist) insurgents could not defeat us with that strategy. Live by the IED. Die by the IED.
On the other hand, lower casualties in the short run for the Taliban was a heavy inducement to try that approach since taking on our forces (mostly US and other Western forces, but increasingly Afghan army troops, too) in direct combat was really bad for personal survival. And the casualties the indiscriminate use of bombs inflicted on civilians was noticed by Afghans, too, who didn't much like the Taliban because of that.
Which is a lesson to us as well. Don't pursue tactics or strategies that lower our casualties in the short run at the expense of winning the war by alienating the Afghan people. Yes, I worry a lot.
