THE OPINIONS EXPRESSED IN THIS BLOG ARE MINE AND ARE NOT NECESSARILY THE SAME AS THOSE OF THE INSTITUTE OF PHYSICS
For more recent material concerning the serious deficiency I have discovered in the C&G Police Syllabus for trainee Police Accident Invesigators see my blog:-
GCSE MATHS/STATISTICS (HGV accidents)
Peter Jones MInstP
Edit Feb 2011
These statistics are to be read in conjunction with those in Para 44 below and further results for LGV’s in my WMPA blog.
The errors in the compilation of the HGV statistics should be easily understood by GCSE students and it would therefore be appropriate if teachers sought the permission of Head Teachers and Governors to send a representative sample of students’ comments to the West Midlands Police Authority. This type of activity provides a valuable link between school and the real world.
It is to be hoped that the WMPA ( and other police authorities) should in future ask the police to display their accident statistics on line so that students and the public can monitor the situation.
The HGV Industry has been concerned for many years over the safety of Articulated Lorries. This is revealed by the fact that they have had Articulated Lorries researched at Bath University, but not rigid HGV’s towing a trailer ( as far as I am aware).
(Put “The Dynamics of Towed Vehicles Killer CJ 2003” in to Google to see a M Eng project report. Page 9 end of para 2 justifies my above comment, and elsewhere in the same document is a description of the testing of the ALKO caravan/trailer stabiliser which I have previously written about in my blogs [para 31a and 36 below])
It can now be seen why we need to have three categories in the accident statistics for HGV’s:- (1) HGV’s (2) Rigid HGV’s towing a trailer and (3) Articulated Lorries.
HGV ACCIDENT STATISTICS
I must emphasise that these statistics contain the last public information (to the best of my knowledge) that the West Midlands Police issued on HGV accidents in their area.
These show that there were 2153 HGV accidents in the West Midlands Police area in the 5 years to 1994.
This gives an average of 8 HGV accidents per week ( national average for all Police forces = 5 per week in the same period) in the West Midlands and according to current DfT statistics more HGV accidents happen on motorways than class “A” roads.
No information was given as to whether the HGV’s were towing a trailer or whether the HGV was a “rigid” or an Articulated Lorry.
Academic entry requirements for police constables to transfer to accident investigation have never been published (as far as I can establish). It is my understanding that there are no entry requirements. Further more I have seen no evidence to show that there is a professional engineer (at least C Eng level) to advise the accident investigators.
Due to problems with the blog software I have pasted these statistics in to a new blog
Peter W Jones MInstP
I REGRET THAT THE BLOG SOFTWARE HAS PLACED THE NEW
A FEW PARAGRAPHS BELOW AFTER PARA 31
Advice for Physics and Maths teachers and the Younger Generation (GCSE and GCE “A” level)
31 Highways Agency Fit to Tow Video
31a Bath University Caravan Research
32 Summary of ideas behind Blogs by Peter W Jones
33 Air Speed Indicators
34 Lobbying Parliament
35 Letter to Dr Tony Wright MP
36 Bath University on Stabilisers (cont)
37 Stabilisers; further details
38 Letter to Mrs Dunwoody MP
39 Caravan Stabilisers explained for
40 IVRA Conversion Kit for Over run Brakes
41 History of New ALKO electronic conversion kit
42 USA Electric Brakes
43 Stabiliser test by Peter W Jones
44 HGV Trailers ( includes accident statistics)
45 Wind induced Road Accident
THE HIGHWAYS AGENCY FIT TO TOW VIDEO (see their web site)
Peter W Jones MInstP
The Highways Agency “Fit to Tow” video, presented by Carol Smillie, has been available for viewing on the inter net for some time.
I welcome the fact that the HA have now modified the DfT presentation of Caravan and Trailer accident statistics. (see my 2006 paper published by the HoC Select Committee on Transport by putting “Caravan and HGV trailer accidents” in to the search engine of www.parliament.uk )
It is well known that the Caravan Club/Caravan Industry policy is that incorrect “load distribution” is the main cause of towing accidents. I do not think it appropriate that this video, with a contribution from ACPO, should promote this viewpoint. Bath University Research has proved that friction based stabilisers do not improve safety and hgv’s can destabilise caravans. The HA in other published items is also now warning caravanners of the effects of strong cross winds and these factors will cause problems even when your caravan is correctly loaded and you are towing with a suitable tow car.
With regard to the towing of trailers with no brakes the HA is assuming that the tow car brakes will be adequate to stop a 0.75 tonne trailer. However, this will not be the case if sharp braking is used at normal motor way speeds. When the tow car brakes sharply, If the trailer is directly in line with the tow car the trailer will rise and smash into the back of the car or pass right over the top if the HA suggested safety chain is unable to prevent this taking place. When the trailer and tow car are not in line the trailer will jack knife, and if the latter is much greater in weight than 50% of the tow car weight ( the legal limit ?) there is a high probability of the tow car being destabilised.
All this follows directly from Newton’s First Law of Motion.
The Institute of Traffic Accident Investigators reported in 2002 in their Journal that they had tested braking a tow car with an unbraked trailer at 40 mph and found that the trailer jack knifed every time.
Also see para 3a of my blog www.caravanaccidents2.wordpress.com for an account of a related accident when the “over run” brakes failed to function.
I WAS WARNED BY THE AUTOMATIC SYSTEM SOME TIME AGO THAT AN ATTEMPT HAD BEEN MADE TO BREAK IN