Road Safety Discussion

rear end crash statistics

  • 1.  rear end crash statistics

    Posted 09 October 2014 09:46
    G'day I read some time ago that the likelihood & severity of a rear end crash at a BAR type intersection is far greater than that of a CHR type intersection. I recall (sounds very high) that there is over a 50% greater chance of having a rear end crash at the BAR intersection than a CHR intersection. I have searched again for this paper but haven't had any luck. Is anyone aware of such statistics as I am trying to push a road safety point & would much prefer a CHR (even with reduced design criteria as per the EDD of Austroads) rather than have a BAR type intersection. Thanks in advance. ------------------------------------------- Adam Mularczyk Team Co-ordinator Development Engineering Wyong Shire Council WYONG NSW -------------------------------------------
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  • 2.  RE: rear end crash statistics

    Posted 11 October 2014 04:34
    Hi Adam,
    One place that may help (not showing the science / statistics / working, but a reference none the less) is the black spot funding crash reduction factors.
    I do these in Victoria and South Australia, but not in New South Wales, so cannot pinpoint where RMS has the information, but it should be there!

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    Hugh Dixon
    Senior Traffic Engineer
    HDS Australia
    Glen Waverley VIC
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  • 3.  RE: rear end crash statistics

    Posted 12 October 2014 21:46
    Adam, you may be thinking of the iRAP Risk Factors (Google iRAP road attribute risk factors intersection type) which gives the relative risk at protected and unprotected right turns.  The 80% reduction figure you quote appears in US data, e.g. Minnesota DOT summary of data currently online that goes back a bit (MDOT Safety Programs Unit - Crash Reduction Factors October, 1986;  Selection Process for Local Highway Safety Projects - Transportation Research Record 847, 1982;UKTRP - 85-6, University of Kentucky; March, 1985. )  These old data tend to hang around a long time and become gospel.Without doubt, removing turning vehicles from the through lane would reduce tail-end crashes but I can't vouch for an 80% reduction.

    You could try contacting the iRAP people to discuss their sources.

    Good luck!

    Ray
    Editor, Road & Transport Research
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    Ray Brindle
    ARRB Group
    Malmsbury VIC
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  • 4.  RE: rear end crash statistics

    Posted 12 October 2014 21:46
    Just in, from a colleague at ARRB:

    "The Austroads guide to road design (Part 4A: Unsignalised and Signalised Intersections) includes some older research by Owen Arndt on this issue. The relevant para is:

     'Research (Arndt 2004) has shown that BAR turn treatments record a rear-end major vehicle crash rate 52 times higher than do CHR turn treatments. The research also found that the rear-end major vehicle crash rate decreases substantially with increased median width, regardless of the type of median (painted, raised or depressed). Commentary 3 provides some more information in relation to the findings in Arndt 2004'. The reference is from Owen's PhD (Arndt, OK 2004, Relationship between unsignalised intersection geometry and accident rates, PhD Thesis, Queensland University of Technology). I haven't reviewed this issue recently, but I am sure there will be more recent research. Shane Turner in NZ has developed crash prediction models for urban and rural intersections, and would probably be a good starting point if you need further info."

    Shane's email address is Shane.A.Turner(AT)mwhglobal.com

     Hope that helps

    Ray



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    Ray Brindle
    ARRB Group
    Malmsbury VIC
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  • 5.  RE: rear end crash statistics

    Posted 11 October 2014 04:34
    Hi Adam.  Urban or rural?  Is there a median?

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    Ray Brindle
    ARRB Group
    Malmsbury VIC
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