2007 trg symposium poster specification j bullas

2007 trg symposium poster specification j bullas

• 1.
  Bituplaning: A LowDry Friction Phenomenon of New Bituminous Road Surfaces John C Bullas BSc MSc MIHT MIAT FGS, Transportation Research Group Telephone: +44 (0) 7946 317467, Email: [email protected], Web: www.trg.soton.ac.uk Stone Mastic Asphalt (SMA, Stone MATRIX Asphalt in the USA) is a negative texture bituminous road surface (NTS) and may possess a thick (15~20 micron) film of bitumen on the outside of the stone particles capable of interrupting the direct contact between the tyre and the stone that leads to the component of friction required to adequately • Maintain the trajectory of a vehicle during cornering • Enable a vehicle to come to a halt in a reasonable distance during a severe braking event Slippery When Dry? The braking distances given in The Highway Code (HMSO 2007) for dry roads correspond to those considered typical by Collision Investigators, these distances are SHORTER than those observed in the experimental trials undertaken (below) A Crash in 1985 on the M4 (NCE, below) that killed 12 resulted from a thicker than normal layer of bitumen on a new HRA (hot rolled asphalt with rolled in pre coated chippings) extending braking distances Research in The Netherlands identified that a thick layer of bitumen on the stone of new porous asphalt (PA) greatly reduced the emergency Dry braking distance for card NOT fitted with ABS (below, DWW (2004)). Signs are routinely used there to warn drivers of the problem (above) Thermal & High Speed Video Imaging of Braking Events The behaviour of road surfaces during emergency braking and the melting of the bitumen film as a result of contact with a sliding tyre was investigated using state-of-the art infrared video (right) and 1000fps high-speed video (above right) imaging. This experimental work was funded by the Highways Agency and administered by Atkins Statistical Analysis A database of 250 simulated emergency braking manoeuvres was classified (above) and analysed using MiniTab and SPSS to identify that the average level of deceleration for a car without ABS is SIGNIFICANTLY lower on a DRY NTS than for a DRY TRADITIONAL ONE Sharing the findings with the global research community Since 2003, the findings of the ongoing research have been disseminated to the worldwide highway engineering and collision investigation profession via publication, and presentation in the UK, New Zealand and Japan including the 2006 ASME Conference in Atlanta USA (below) Sponsorship & Support The Author wishes to acknowledge the valuable contribution of Dr N B Hounsell (Academic Supervisor), Atkins Ltd, the Highways Agency, Dynatest (UK) Ltd (financial sponsorship), Dorset, Devon & Cornwall, Greater Manchester, Metropolitan, Gwent, Lancashire, Humberside and Suffolk Police Services, Virginia Dept. of Transportation (VDOT) & NOC Southampton (for data provision), Turnkey, Vericom, Kistler, and FLIR-UK for specialist equipment hire or loan