2013 Session: 524

• Impact Conditions Associated with Cable Median Barrier Failures
  Abstract: Cross-median crashes are disproportionately represented with respect to fatalities on divided roadways. Many state DOTs seeking to mitigate cross-median crash risk installed cable median barriers, due to their versatility, flexibility, and low cost. However, cable median barriers are also roadside hazards. Conditions associated with cable median barrier containment failures and crash severity were investigated in this study. The 85th percentile trajectory angle associated with severe cable median barrier crashes was calculated to be 39 degrees. Severe median crashes frequently occurred with larger orientation angles than trajectory angles. Although high-tension cable median barriers have many advantages over low-tension systems, low-tension systems had the lowest severe crash rate of 1.7% despite penetration and rollover rates of 9.1% and 7.8%, respectively. Individual distributions of penetration and rollover crashes were not statistically different when compared by vehicle classification. Thus, vehicle make, model, and type may be equally important in full-scale crash testing as test vehicle weight and CG height. Future cable median barrier tests should be conducted at a CG trajectory angle of 39 degrees with large car and SUV vehicles to maximize safety potential of these systems. With these changes to full-scale test procedures, cable median barrier containment failure rates would decrease and many lives would be saved.
  Authors: Stolle, Cody Steven; Sicking, Dean L.
  Authors: Stolle, Cody Steven; Sicking, Dean L.
  Year: 2013
  Document Type: Paper
  Subject: Design; Safety and Human Factors
  Session: 524
  Paper Number: 13-1564
• Injury Risk due to Side Impact of Non-Tracking Vehicles into Guardrail
  Abstract: One of the most dangerous types of guardrail crash is side impact. Of particular concern is when a non-tracking vehicle slides sideways into a guardrail end treatment. This study has investigated the issue of end terminal side crashes using a dataset of 142 guardrail crashes extracted from the National Automotive Sampling System / Crashworthiness Data System (NASS/CDS). Side crashes involving an end terminal are substantially over-represented in driver injuries. End terminal contact occurs in about 25% of all guardrail side crashes but represents almost 70% of driver injuries. Non-crashworthy terminals are roughly twice as likely as crashworthy designs to cause serious injury. Terminals are also about twice as likely to initiate rollover than length of need. When injuries due to drivers in rollover, unbelted drivers and driver ejection are accounted for, the risk presented by terminal contact is accentuated, as is the difference between cars, light trucks, and vans in terminal impacts.
  Authors: Johnson, Nicholas Sean; Gabler, Hampton Clay
  Authors: Johnson, Nicholas Sean; Gabler, Hampton Clay
  Year: 2013
  Document Type: Paper
  Subject: Design; Safety and Human Factors
  Session: 524
  Paper Number: 13-4694
• Motorcycle Impacts into Roadside Barriers: Is The European Crash Test Standard Comprehensive Enough?
  Abstract: The current European motorcycle-into-barrier crash standard EN 1317-8 and its relevance to Australian motorcycle fatalities are reviewed. The data collection and analysis of 78 Australian fatalities described in the paper are used to justify the review. Each year around fifteen motorcyclists die in Australia impacting a road safety barrier. A retrospective analysis of the fatalities during the period 2001 to 2006 was carried out. Consistent with European findings, around half the motorcyclist impacted the barrier in the upright posture whereas half slid into the barrier. The mean pre-crash speeds and impact angles were 100.8 km/h and 15.4° respectively. Body regions injured were similar across different barrier types (concrete, wire-rope and W-beam) and crash postures. The thorax body region had the highest incidence of injury and maximum injury in fatal motorcycle-barrier crashes, followed by the head region. Moreover, thorax and pelvis injury had a greater association with sliding crashes than with those in the upright posture. The existing European standard EN 1317-8 only addresses the sliding mechanism, uses a head injury criterion, and does not specify any thorax injury criterion. The high incidence of upright crashes and thorax injury in crash data points to a need to introduce an upright crash test and a thorax criterion as additional requirements in any motorcycle-into-barrier crashworthiness test matrix. The authors propose that a thorax injury criterion and an additional test should be introduced, which requires the rider to impact the barrier upright and then slide along the top of the barrier.
  Authors: Grzebieta, Raphael H.; Bambach, Mike; McIntosh, Andrew
  Authors: Grzebieta, Raphael H.; Bambach, Mike; McIntosh, Andrew
  Year: 2013
  Document Type: Paper
  Subject: Design; Safety and Human Factors
  Session: 524
  Paper Number: 13-5373
• Retrofit Bridge Rail Design and Testing for Historic Texas Steel Truss Bridge
  Abstract: The State Loop 481 Steel Truss Bridge over the Llano River in Junction, Texas is classified as a historic structure. This bridge is approximately 1,423 feet in length. The vintage bridge railing used on this bridge attaches directly to the steel truss members and does not meet the current AASHTO Test Level 2 (TL-2) Strength Requirements (2). Many of the supporting truss members were not adequate to resist the TL-2 crash forces. The purpose of this research was to design a crashworthy retrofit bridge rail that meets the current strength AASHTO TL-2 Strength Requirements (2) without overstressing the supporting truss members. The new design maintains the historic appearance of the structure. This paper presents details of the new bridge rail design and an analytical procedure for determining the magnitude of force transmitted to the supporting truss members. Crushable pipe block outs located between the new retrofit rail design and the truss members were developed as part of this research and were used to minimize the crash forces transmitted to the steel truss members. The bridge rail design presented herein was successfully crash tested in accordance with NCHRP Report 350 TL-2 Requirements (1). A bridge rail expansion splice was developed for this bridge rail design and was successfully crash tested in accordance with NCHRP Report 350 TL-3 Requirements (1). Details of this expansion splice are also presented in this paper. The results of this research, the new bridge rail design, design procedure, and the crash testing results are presented in this paper.
  Authors: Williams, William Frederick
  Authors: Williams, William Frederick
  Year: 2013
  Document Type: Paper
  Subject: Design; Safety and Human Factors
  Session: 524
  Paper Number: 13-4756
  Practice-Ready: Yes
• Impact Conditions Associated with Cable Median Barrier Failures
  Authors: Stolle, Cody
  Authors: Stolle, Cody
  Year: 2013
  Document Type: Presentation
  Subject: Design; Safety and Human Factors
  Session: 524
  Paper Number: 13-1564
• Injury Risk due to Side Impact of Non-Tracking Vehicles into Guardrail
  Authors: Johnson, Nicholas
  Authors: Johnson, Nicholas
  Year: 2013
  Document Type: Presentation
  Subject: Design; Safety and Human Factors
  Session: 524
  Paper Number: 13-4694
• Retrofit Bridge Rail Design and Testing for Historic Texas Steel Truss Bridge
  Authors: Williams, William
  Authors: Williams, William
  Year: 2013
  Document Type: Presentation
  Subject: Design; Safety and Human Factors
  Session: 524
  Paper Number: 13-4756
• Motorcycle Impacts into Roadside Barriers: Is The European Crash Test Standard Comprehensive Enough?
  Authors: Grzebieta, Raphael
  Authors: Grzebieta, Raphael
  Year: 2013
  Document Type: Presentation
  Subject: Design; Safety and Human Factors
  Session: 524
  Paper Number: 13-5373