BACKGROUND

Motorcycle crashes with roadside hardware are a challenging issue for state departments of transportation (DOTs). According to the National Highway Traffic Safety Administration (NHTSA), in 2021 the fatality rate for motorcyclists was almost 24 times the fatality rate for passenger car occupants. In the same year, 24 percent of motorcycles involved in fatal crashes collided with fixed objects. Overall, collisions with fixed objects in the roadside environment (including trees, sign supports, lamp posts, and barriers) represent much higher risk of fatality and incapacitating injury for motorcyclists than for passenger car occupants.

Among types of roadside hardware, crashes with longitudinal barriers are a significant issue for motorcyclists; in 2017 motorcyclists accounted for 40 percent of guardrail related fatalities. Historically, roadside safety systems such as guardrail and concrete barriers have been designed to redirect errant passenger vehicles and generally have not taken into consideration potential impacts by vulnerable users such as motorcycle riders.

International crash testing standards, such as the European CEN/TS 17342:2019 Road Restraint Systems, include consideration of motorcyclists in barrier design. In addition, several DOTs have taken independent action toward incorporating motorcyclist safety into their barrier system(s). However, the American Association of State Highway and Transportation Officials (AASHTO) Manual for Assessing Safety Hardware (MASH) does not currently contain protocols for testing roadside barriers for motorcyclist impacts. 

Research is needed to develop national guidelines with procedures for motorcycle testing and evaluation of roadside hardware with an emphasis on longitudinal barriers.

OBJECTIVE

The objective of this research is to develop guidelines with procedures for crash testing roadside safety hardware for motorcycles with an emphasis on longitudinal barriers. 

Accomplishment of the project objective will require at least the following tasks.

TASKS

PHASE I – Planning 

Task 1. Conduct a literature review of relevant research regarding roadside hardware impacted by motorcyclists including testing and evaluation methods. The review shall include published and unpublished research conducted in the United States and internationally.

Task 2. Conduct a critical analysis and synthesis of the results of the literature review and identify knowledge gaps and opportunities. Identify priorities for research as part of this project and recommended future research and testing.

Task 3. Develop a method to achieve the project objective. At a minimum, for sliding and upright crash modes, the method shall include approaches to: 

• Determine specifications for the motorcycle test vehicle(s);
• Determine specifications for test dummies and surrogate devices (e.g., sensors, helmet, weight, equipment, upright attachment to motorcycle);
• Determine the most representative impact conditions, including speed and impact angle; 
• Determine factors for developing evaluation criteria, including but not limited to considering tolerable limits for:
  • Head injury, chest compression, neck compression/tension/flexion;
  • Snagging, laceration, or amputation; and
  • Vaulting; and
• Propose the number and type of crash tests or other methods to pilot the test procedures as part of this project.

Task 4. Identify commonly used MASH-compliant longitudinal barrier systems as a basic configuration (with or without modification) that may be used to evaluate the test conditions to determine if the evaluation criteria are achievable and implementable. Propose a barrier system(s) to demonstrate the procedures.

Task 5. Develop an annotated outline of the draft guidelines. 

Task 6. Prepare Interim Report No. 1 that documents Tasks 1 through 5 and provides an updated work plan for the remainder of the research.

PHASE II – Methodology Execution

Task 7. Execute the method in the approved Interim Report No.1. Confirm the proposed barrier system for crash testing or other pilot test methods. Summarize findings in a technical memorandum and participate in a virtual meeting to debrief the NCHRP panel.

Task 8. Execute crash testing or other pilot test methods per the approved Interim Report No 1. Document findings in a technical memorandum.

Task 9. Revise the annotated outline of the draft guidelines and provide a sample chapter. The sample chapter will be selected by the NCHRP and shall be publication-ready.

Task 10. Prepare Interim Report No. 2 that documents the results of Tasks 7 through 9 and provides an updated work plan for the remainder of the project. 

PHASE III – Final Deliverables

Task 11. Prepare the draft guidelines and draft content for consideration by AASHTO for inclusion in its next update of the MASH (AASHTO deliverable). The draft guide and AASHTO deliverable are due at least 6 months before the contract end date.

Task 12. Revise the draft guidelines and the AASHTO deliverable per the NCHRP’s review comments.

Task 13. Prepare a presentation of the guidelines for the AASHTO Technical Committee on Roadside Safety.

Task 14. Prepare final deliverables, including:

• The AASHTO deliverable;
• A research report, including an executive summary, that documents all research, findings, the guidelines, and project efforts;
• A PowerPoint presentation with speaker notes that summarizes the project and distinctly illustrates for the audience how the research can be applied in their organization;
• Supporting data files including photos and videos;
• The presentation of the guidelines to the AASHTO Technical Committee on Roadside Safety; and
• A technical memorandum titled “Implementation of Research Findings and Products”.

STATUS: Research in progress.