Mr. Garden said the bus had come to a stop 60 feet south of the intersection.
Mr. Garden said that most of the injuries to passengers appeared to be minor.
"No one can remember the box ever falling off before," Mr. Garden said.
Mr. Garden said emergency inspections on the R-33's might take two or three days.
The board is expected to approve a 15-cent increase, Mr. Garden said.
Replacing them will cost about $5.2 million, Mr. Garden said.
The four other youths were not hurt, Mr. Garden said.
Mr. Garden said bus drivers do occasionally hit something without noticing it.
Mr. Garden said that the lines affected by the change are some of the least traveled in the system.
"We'll be doing the work while providing service every day," Mr. Garden said.