They are built with a v-shaped bottom to deflect blasts from roadside bombs, but the armor was no match for a suicide bomb that, according to a statement from the Taliban, was as large as any bomb seen in the capital.
In May 2009, the Taliban claimed a similar size bomb was used to kill 4 serving colonels in the same area of Kabul as today's attack.
During today's attack, at least two medivac helicopters landed at the scene and evacuated some of the wounded.
In addition to this attack, a young female suicide bomber on foot attacked government offices in eastern Asadabad city, killing herself and wounding at least four.
In another separate attack in southern Afghanistan, at least three Australian NATO soldiers were killed after an Afghan soldier they had been training with turned his gun on them.
In 2011, there have been at least 12 cases of Afghan forces turning their guns on their foreign mentors; there were only 13 such cases between 2005 and 2010, according to a tally by the Washington think tank Brookings.