Mr. Carnahan of the pupil-transportation directors’ association said the chances of a school bus being struck from such an angle are slim and, thus, that the buses appear to pose little immediate danger.
The Chicago-based company last month said it agreed to voluntarily recall the buses after federal tests showed the fuel tanks could rupture and leak after a collision.
Both Navistar and the National Highway Traffic Safety Administration stressed that they did not know of any accidents in which the fuel tanks had ruptured, even though some of the buses involved in the recall are more than 10 years old.
“School buses remain the safest form of transportation for our children,’' Secretary of Transportation Andrew H. Card Jr. said in a statement issued late last month.
Nevertheless, Mr. Card added, “it is imperative that buses not meeting the federal safety standard are fixed promptly by Navistar.’'
Further Recall Possible
The buses affected have International brand school-bus chassis manufactured since Sept. 1, 1978, according to a statement issued by Navistar.
The firm, which builds more than one-third of the school-bus chassis sold in the United States, said it plans to recall at least 24,000 buses--all of those with 35-gallon fuel tanks.
Navistar expects to notify school districts and bus operators through the United States and Canada this month, and is developing and testing ways to fix the problem, company officials said. They estimated the recall will cost the company at least $1 million.
William A. Boehly, the associate administrator for enforcement at the N.H.T.S.A., said the company should recall an additional 161,000 bus chassis equipped with 65-gallon tanks.
Although the N.H.T.S.A. did not crash test the 65-gallon-tank chassis, the configuration and placement of the larger tank is similar to that of the smaller model and the larger tanks generally are regarded as more vulnerable to rupture, Mr. Boehly said.
Navistar plans to do additional tests before deciding whether to recall buses with the larger tanks, a company spokesman said.
If all 185,000 school-bus chassis manufactured by the company since 1978 are recalled, it would affect nearly half of the nation’s fleet of about 390,000 school buses and could cost the company as much as $20 million.
Don M. Carnahan, the director of pupil transportation for Washington State and president of the National Association of State Directors of Pupil Transportation Services, last month questioned whether Navistar can fix all of the buses it has recalled so far by the start of the new school year.
Little Immediate Danger
The defect found in the Navistar chassis had not been located in previous tests conducted over 16 years by the N.H.T.S.A. and the company.
In the most recent test, conducted June 23, N.H.T.S.A. engineers examined the bottom of a school-bus chassis with a 35-gallon tank and tried to pinpoint its most vulnerable spot, Mr. Boehly said.
The testers rammed a steel barrier into a stationary school bus to simulate a car approaching from the right, rear side and hitting that end of the bus at 30 miles an hour.
A metal cage intended to protect the gas tank was sheared away and punctured the tank, causing several gallons of fuel to spill quickly, Mr. Boehly said.
Under federal law, a gasoline tank can leak no more than five ounces of fuel in a test.
Mr. Carnahan of the pupil-transportation directors’ association said the chances of a school bus being struck from such an angle are slim and, thus, that the buses appear to pose little immediate danger.
“We have had 13 or 14 years of experience here and have not experienced that kind of collision,’' Mr. Carnahan said.
Navistar officials have suggested that customers with questions about the recall call the firm toll-free at (800) 448-7825.
The National Highway Traffic Safety Administration also will answer questions about this and other recalls at (800) 424-9393.
