Comments by
PROFESSOR P.N. JOUBERT. OAM, B.E., M.E., FIE Aust., FSAE, MSNAME, FTSE,
On preliminary document titled,
OVERVIEW OF RESEARCH AND PRACTICE
prepared by
Queensland School Transport Safety Task Force, July 2001
1. My name is Professor Peter Numa Joubert and I reside at 33 Walbundry Avenue, Balwyn North, 3104, Victoria. I was formerly the Professor of Mechanical Engineering at the University of Melbourne and currently still work there as a non-salaried Professorial Fellow supervising research of two PhD students and one post-doctorial research fellow.
2. Of pertinent interest is that I was a foundation member of the various titled advisory committees in vehicle design which were responsible for forming and introducing the vehicle design rules (ADR’s). For many years I chaired sub-committees on occupant protection, trucks and buses and brakes. I left the committee when I retired in 1989. I continue motor accident activity as a consultant. My curriculum vitae on motor vehicle matters is attached.
3. After I reviewed the literature on truck and bus safety in February 1974, on behalf of the Federal Department of Transport, it became obvious that seat strength was the immediate obvious source of weakness in the event of bus crashes. I discovered certain buses where the seats were attached by screws into the plywood floor; their resistance to impact was negligible. It is useless thinking about seatbelts if the bus structure including seats are not strong enough to carry the loads imposed in an impact by the seatbelts or by the unbelted seated occupants against the back of the seat in front of them.
One particularly nasty accident in the UK involved a head-on resulting in the shear failure of all the cast aluminium seat supports leaving sharp jagged edges, which tore gaping wounds on the passengers as they were flung forward to the front of the bus. There have been many similar accidents where the seats have become loose.
4. I was then supported by the Government in a study of bus seats and anchorages. A knowledgeable colleague, Dr. Williams, helped with the project (your reference 16). Mr. Dixon was a research student. After this I agitated for increased bus seat strength, seat belts on exposed seats and a seat belt for the driver but was always put off by arguments such as those put forward by Henderson, and mentioned in report on page 24, second column lines 28 to 32, “. . . . .costs thousands of times more than the value of the injuries saved”.
5. Then came the accident on the 20th of October 1989. A semi-trailer ploughed head-on into a coach on the Pacific Highway at Grafton, NSW. Twenty passengers died and 15 were injured. Of particular note was the effect on injuries due to seat and seat mountings breaking free. However, this was not quite bad enough to cause positive action until 2 months later, on 22nd December 1989, two coaches collided head-on at Kempsey, NSW. Thirty-five people died and 39 were injured. Thereafter design rules for seat belts in coaches; improved seat and seat anchorage strength and emergency exits became the most urgent priority.
6. This brings us to one of my main points, namely, bus accidents with school children and especially coaches on freeways at high speed may be rare events but when they occur they are so horrific as to bring the wrath of God and especially the wrath of the parents of the children upon the heads of the bureaucrats and the members of the investigating committees who hide behind statistics for their lack of proper protection of school children.
7. When committees such as yours are confronted with statistics they may be blinded from alternative views. Pak Poy was a well-known Victorian Engineer involved in road safety. He looked at bus accident statistics (see my 1973 report), by considering the number of buses which shows a much higher involvement for buses compared to cars. This is the opposite of what is told to us about bus accident involvement, because these are usually worked out on the basis of accidents per passenger mile. Because of the large numbers of passengers per bus compared to cars, the result is a low involvement of buses compared to that of cars.
Whatever the statistical measure the results of a bus accident at high speed are most likely to be horrific.
It was the occurrence of the two such horrific events, Grafton and Kempsey, which caused the sudden switch to bus safety early in 1990 led by the political reaction of the NSW Government.
I suggest to you, members of the committee, if buses are allowed to take large numbers of standing children at high speeds down freeways in due course there will be a nasty accident. It would be better in my opinion to act before the accident.
8. I now wish to comment on the paper by Dr. Michael Henderson, 1996b (your reference number 23), where some of his remarks have been given the incorrect meaning and where I consider he has been misleading in other remarks. Firstly, he does not say standees are as safe as seated passengers (page two of your report, second column, lines 31 and 32). Rather does he say, “Unless the bus seats are designed to increase safety the standing passenger is at no greater risk of injury than one who is seated.” (page 16, lines 29 – 31). This qualification is critical.
His opinion may have had some basis in a low speed impact with older buses, but as your State now, - “has design standards for impact padding on and around seats which came into effect from 1997 with partial retrospectivity”, (page 2, 1st column), this aspect, the padding of the seat, is being solved. It needs to be expedited.
9. I do suggest your report should include a sub section titled “Safe Seats” under the main heading of “Bus Design for Safety”. In my opinion this is serious omission in your report. It needs enlarging over what there is at present. It is critical for bus safety that seats do not become loose.
10. But to return to Dr. Henderson, with a high-speed crash the standing passengers have no chance whatever of maintaining their equilibrium and move forward with the pre-impact velocity of the bus while the bus structure has come forcible to rest. If there are a number of standing passengers then the forces on the first passenger on impact with the front of the bus, are increased by the number of passengers standing behind him.
So if there are say, 6 passengers standing together in a row down the aisle of the bus, then the impact force on the first standee is,
F1 = (m1+m2+m3+m4+m5+m6) X deceleration
Where m is the persons’ mass.
The impact force on the second person
F2 = (m2+m3+m4+m5+m6) X deceleration
and so on.
It is only the last person, number 6, who receives the lowest force,
F6 = m6 X deceleration
Dr. Hendersons’ concept that – “the risk per standee in a crash will be lower if there are a large number of standees on the bus” (page 16, lines 24 – 25), is not only misleading it is incorrect. It should be noted that his training is medical and not that of an engineer or applied mathematician.
11. It is my firm opinion that carrying standees in buses on freeways at high speeds is a situation to be avoided.
12. I would draw attention to the contradictory attitudes to vehicle safety for school children. Every time our children travel in a car they are exposed to road safety measures. As babies they travel in specially restrained cots. As mobile children they are restrained in a safety harness, and as they grow larger, in the adult seatbelt. The chances of being involved in an injury producing accident takes on average fifty years of driving which is a low risk. To be involved in a death takes 150 years. Yet the children adapt completely to the situation. Opposed to this when they travel on a bus they don’t wear a seatbelts, and are even forced to stand while the bus is travelling at high speed which is a much more risky situation on the face of it, than travelling in a car with a seatbelt.
Your committee of psychologists, medicos and educationalists might think about this inconsistent attitude.
13. Do you intend studying the role of tyres and retreaded tyres? You should and see my 1973 report, pp 54 – 57.
14. I note (p.29) you intend interviewing experts in road safety. I would be happy to be interviewed.
15. I consider you have prepared an excellent report, and welcome the chance to comment.