Comments on: Westbound Bay Bridge closed by big rig rollover http://sf.metblogs.com/2009/10/14/westbound-bay-bridge-closed-by-big-rig-rollover/ Sat, 27 Aug 2011 20:30:44 +0000 hourly 1 http://wordpress.org/?v=3.2.1 By: More than 40 crashes on S-curve of death, CHP says | San Francisco Metblogs http://sf.metblogs.com/2009/10/14/westbound-bay-bridge-closed-by-big-rig-rollover/comment-page-1/#comment-9241 More than 40 crashes on S-curve of death, CHP says | San Francisco Metblogs Mon, 09 Nov 2009 17:17:07 +0000 http://sf.metblogs.com/?p=6191#comment-9241 [...] over the Labor Day weekend as part of the decade-long Bay Bridge earthquake retrofit project. After a big rig crashed on the curve Oct. 14, spilling cargo across four lanes, CalTrans lowered the speed limit on the curve to 35 m.p.h. and installed new signs, but evidently [...] [...] over the Labor Day weekend as part of the decade-long Bay Bridge earthquake retrofit project. After a big rig crashed on the curve Oct. 14, spilling cargo across four lanes, CalTrans lowered the speed limit on the curve to 35 m.p.h. and installed new signs, but evidently [...]

]]> By: Arnie from Oz http://sf.metblogs.com/2009/10/14/westbound-bay-bridge-closed-by-big-rig-rollover/comment-page-1/#comment-9156 Arnie from Oz Fri, 16 Oct 2009 09:54:05 +0000 http://sf.metblogs.com/?p=6191#comment-9156 I expect the prime mover's drive suspension was air suspended. Air suspended prime movers simply don't like 'S' curves. Calculations indicate drivers must negotiate 'S' curves some 30% slower than if the curves were stand along curves. Standard air suspensions have numerous inherent deficiencies. Authorities must be aware of these problems and most importantly enforce simple improvements to make them vastly safer. Improved driver education is also essential. Likewise road designers should have avoided introducing a 'S' curve. Most likely the curve/s possess the most adverse radius. If this is a new 'S' this accident won't be the last. I expect the prime mover’s drive suspension was air suspended.
Air suspended prime movers simply don’t like ‘S’ curves. Calculations indicate drivers must negotiate ‘S’ curves some 30% slower than if the curves were stand along curves.

Standard air suspensions have numerous inherent deficiencies. Authorities must be aware of these problems and most importantly enforce simple improvements to make them vastly safer. Improved driver education is also essential. Likewise road designers should have avoided introducing a ‘S’ curve. Most likely the curve/s possess the most adverse radius. If this is a new ‘S’ this accident won’t be the last.

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