Almost 150 Houston schoolbuses rescued victims

From this:

About 300 Houston Independent School District bus drivers and other employees spent Sunday on almost 150 district school buses rescuing hurricane victims from the waterlogged streets of New Orleans.
HISD buses also transported military troops from an airfield to duty within flooded areas...
...The vehicles headed for New Orleans in convoy Saturday night at the request of the Louisiana governor's office. District police and mechanics also participated.

(Via this)