Monday, April 20, 2009

Bus Crash at Rawang 6 Died General Investigation Findings

1. Today I read a letter in News Straits Times entitled No Reason to Keep Findings a Secret with regard to the latest bus crash at Rawang, involving 6 deaths. The author of the letter was conveying his concerns and disappointment to the authorities who mostly try not to share the findings on public. To be truth, there are many reasons to not share it on the public but from my opinion, even so, it is quite unfair to the public. They are actually deserved to know as this is a national issue.

2. This is the preliminary findings in response to the letter. I personally went to the crash site the day of the accident and MIROS has been given task to do the analysis and reconstruct the crash to determine the cause of the accident. Let me start with the sketch diagram of the crash, as shown below and go through with the issues.

3. Speeding. So basically, based on the evidence found from the crash site (skid marks and etc), the bus went to the middle guardrail, hit it, bounced a bit and then hit back, then bounce straight to the rest position. Based on conservation of energy theory, we determine that the speed before the bus hit the median was in the range of 87.1km/h to 100.2km/h with assumption the speed of the bus after it left the median area to the rest position was 10km/h and 50km/h respectively.

4. Improper Guardrail Installation. The W-Beam has been installed on the embankment slope. From the standard guidelines, the slope must not exceed 9.46 degrees but we found the slope of installation was at 23 degrees. Also, the required dynamic clearance for installation was supposedly is 1.2m but on the site, we found it to be only 0.5m.

5. Guardrail Intrusion Mechanism. The W-beam broke off from the mounting post leaving its end hanging and intruded the frontal part of the bus through the metal sheet which is vulnerable with such impact. The section intruded deep into the bus longitudinally which killed ALL six (6) passengers of the lower deck. The guardrail would have not intruded the inside of the bus if the contact impact was resisted by the strong and stiff structure of the bus chassis at the right level height.

6. Driver Fatigue at Wee Hours. Nobody can drive normally during wee hours as our body biological clock is meant only to rest and sleeping during this time. The bus driver was in fatigue condition and possibly falls asleep based on pre impact skid mark before crash (parallel with road stretch).

7. In conclusion, this is just general findings (specific ones are still confidential) and these analyses are not meant to blame anybody. It is solely means for the research and recommendations to related government agencies for improvement in the future so that no similar cases will be happening again.

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