Project: Protective Helmets: Motorcycle, Pedalcycle and Human Head Tolerance

Reference: S100L/VF

Last update: 27/08/2003 15:37:47

Objectives

This project will investigate the tolerance of the human head and brain to linear and rotational accelerations as a result of impacts, and then seek to establish a test criteria for protective helmets that will ensure the optimum protection is offered within the physical constraints of the helmet size and the materials available for use. The project will also investigate alternative materials for improved energy absorption characteristics and develop a prototype helmet using such materials that will optimise the protection available to the wearer.

Description

The majority of fatal and serious injuries to two wheeled motor vehicle users are attributed to head injuries. By developing test criteria for protective helmets that will better protect the head and brain in the event of an impact, the number of casualties should be reduced. Significant improvements to the international crash helmet standard (UN-ECE Regulation 22) have been achieved and further requirements entered into force in June 2000. Developments of standards for the longer term are being co-ordinated initially through a European Co-operation in the Field of Scientific and Technology Research (COST) project. This project brings together the combined research efforts of France, Germany, Hungary, Italy, the Netherlands, Switzerland and the United Kingdom. Although not a signatory, Finland is also participating. The principle objective is to establish the tolerance of the human head and neck to the main injuries sustained by motorcyclists and, based on this, to propose a specification for testing the next generation of motorcycle helmets. The COST project is to establish the tolerance of the head to impact so that helmet design can be optimised and has been extended to include physiological and ergonomic aspects such as comfort, noise and ventilation.

Contractor(s)

TRL Limited
Crowthorne House, Nine Mile Ride, Wokingham, Berkshire, RG40 3GA
+44 (0)1344 773131

Contract details

Cost to the Department: £1,720,000.00

Actual start date: 26 February 1992

Actual completion date: 31 December 2002

Publication(s)

PR/SE/260/97. Helmet and Head Injury Research. A Progress Report. Volume 1
Author: TRL Ltd
Publication date: 01/02/1997
Unpublished
Source: Contact steve.gillingham@dft.gsi.gov.uk

PR/SE/260/97. Helmet and Head Injury Research. A Progress Report. Volume 2
Author: TRL Ltd
Publication date: 01/02/1997
Unpublished
Source: Contact steve.gillingham@dft.gsi.gov.uk

PR/VE/162/95. Improved Motorcycle Design. Part 1
Author: TRL Ltd
Publication date: 01/12/1996
Unpublished
Source: Contact steve.gillingham@dft.gsi.gov.uk
More information: http://www.trl.co.uk/static/dft/trl_pr_ve_162_95.pdf

Motorcycle Safety Helmets. A Literature Review
Author: TRL Ltd
Publication date: 01/12/1997
Unpublished
Source: Contact steve.gillingham@dft.gsi.gov.uk

Accident Description and Analysis of Motorcycle Safety Helmets. Interim Report
Author: TRL Ltd
Publication date: 01/12/1997
Unpublished
Source: Compressed Word file for download at www.cordis.lu/cost-transport/src/pub-327.htm

Accident Description and Analysis of Motorcycle Safety Helmets. Final Report
Author: Hannover University
Publication date: 01/12/1999
Unpublished
Source: D. Otte, Hannover University, Accident Research Unit

Accident Investigation. Final Report
Author: Hannover University
Publication date: 01/12/1999
Unpublished
Source: D. Otte, Hannover University, Accident Research Unit

Working Group on Headforms. Final Report
Author: TRL Ltd
Publication date: 01/12/1999
Unpublished
Source: Contact steve.gillingham@dft.gsi.gov.uk

Accident Reconstruction Working Group. Final Report
Author: TRL Ltd
Publication date: 01/12/2000
Unpublished
Source: Contact steve.gillingham@dft.gsi.gov.uk

Working Group on Mathematical Modelling of the Head, Neck and Helmet. Final Report
Author: TRL Ltd
Publication date: 01/12/2000
Unpublished
Source: Contact steve.gillingham@dft.gsi.gov.uk

Motorcycle Safety Helmet Test Procedures. Interim Report
Author: TRL Ltd
Publication date: 01/12/2000
Unpublished
Source: Word file available for download at www.cordis.lu/cost-transport/src/pub-327.htm

Paper. Validation of a 3D Anatomic Head Model and Replication of Head Impact in Motorcycle Accidents by Finite Element Modelling. 41st Stapp Car Crash Conference 1997
Author: TRL Ltd
Publication date: 01/03/1997
Unpublished
Source: Contact steve.gillingham@dft.gsi.gov.uk

Paper. Impact Mechanisms of Helmet Protected Heads in Motorcycle Accidents Accidental Study of COST 327. Motorcycle Safety Conference 1998. Organised by IFZ (Institute for Motorcycle Safety)
Author: TRL Ltd
Publication date: 01/03/1998
Unpublished
Source: Contact steve.gillingham@dft.gsi.gov.uk

Paper. Accident Description and Analysis of Motorcycle Safety Helmets. Final Report
Author: Hannover University
Publication date: 01/03/1999
Unpublished
Source: D. Otte, Hannover University, Accident Research Unit

Paper. COST 327. Motorcycle Safety Helmets - Injuries, Analysis and Simulation. 2nd European Road Research Conference
Author: TRL Ltd
Publication date: 01/03/1999
Unpublished
Source: Contact steve.gillingham@dft.gsi.gov.uk

Data Gathering Analysis Study on Motorcycle Safety Helmets
Author: Hannover University
Publication date: 01/12/1999
Unpublished
Source: D. Otte, Hannover University, Accident Research Unit

Paper. Motorcyclists Head Injuries: Mechanisms Identified from Accident Reconstruction and Helmet Damage Replication. IRCOBI 1999
Author: TRL Ltd
Publication date: 01/03/1999
Unpublished
Source: Contact steve.gillingham@dft.gsi.gov.uk

Validation of a Full Face Protective Helmet Finite Element Model and Coupling with a Human Head Model
Author: TRL Ltd
Publication date: 01/12/1999
Unpublished
Source: Contact steve.gillingham@dft.gsi.gov.uk

Paper. Helmets, Protective Clothing and the Effect on Injury. Helmets CLT Conference 2000
Author: TRL Ltd
Publication date: 01/03/2000
Unpublished
Source: Contact steve.gillingham@dft.gsi.gov.uk

Paper. Head Tolerance Limits Derived from Numerical Replication of Real World Accidents. IRCOBI 2000
Author: TRL Ltd
Publication date: 01/03/2000
Unpublished
Source: Contact steve.gillingham@dft.gsi.gov.uk

PR/SE/592/02. Investigation of the Scottish General Hospital Motorcycle Accident Database with Respect to Climatic Factors
Author: TRL Ltd
Publication date: 01/11/2002
Unpublished
Source: Contact steve.gillingham@dft.gsi.gov.uk
More information: http://www.trl.co.uk/static/dft/trl_pr_se_592_02.pdf

PR/SE/469/98. Comparison of the Variability in Oblique Anvil Test Results from Four European Laboratories
Author: TRL Ltd
Publication date: 27/08/1997
Unpublished
Source: Contact steve.gillingham@dft.gsi.gov.uk
More information: http://www.trl.co.uk/static/dft/pr_se_469_98.pdf

PR/SE/459/98. Helmet and Head Injury Research. A Progress Report. Appendix F. Replication of a Full Scale Motorcycle Impact Test 10P
Author: TRL Ltd
Publication date: 01/02/1998
Unpublished
Source: Contact steve.gillingham@dft.gsi.gov.uk
More information: http://www.trl.co.uk/static/dft/pr_se_459_98.pdf

PR/VE/514/99. Improved Motorcycle design. Part 2. Energy Absorbing Materials
Author: TRL Ltd
Publication date: 01/12/1999
Unpublished
Source: Contact: steve.gillingham@dft.gsi.gov.uk
More information: http://www.trl.co.uk/static/dft/trl_pr_se_514_99.pdf

PR/SE/263/97. Improved Motorcycle Helmet Design. Part 3. The Relationship Between Shell Design and Injury Potential
Author: TRL Ltd
Publication date: 01/12/1997
Unpublished
Source: Contact: steve.gillingham@dft.gsi.gov.uk
More information: http://www.trl.co.uk/static/dft/trl_pr_se_263_97.pdf

Summary of results

  1. Nationally, it was found that whilst 20% of riders admitted to hospital suffered a head injury (indicating that current helmets offer good protection),16% sustained a head injury of AIS 2-4 suggesting that improvements to helmets could offer worthwhile injury savings. Of the 253 head/neck injury cases chosen for collaborative analysis, 73% of casualties had leg injuries, 67% head injuries, 57% thorax injuries, and 27% neck injuries. Helmet damage was evenly distributed around the helmet apart from the crown, where impacts were significantly less frequent at a tenth of those experienced elsewhere. Head and brain injuries were mostly attributed to an indirect force (58%), followed by a direct force (31%) and specifically to an indirect force directly opposite (11%). Rotational motion was found to be the cause of 60% of AIS 2 and above injuries and linear motion the cause of 30%. Severe neck injuries were always associated with severe head injuries. An increase in energy absorption of some 24% would reduce 20% of AIS 5-6 casualties to AIS 2-4. It was also found that 12.4% of motorcyclists lost their helmets in accidents indicating that helmet retention should be improved. Climatic conditions could have been a prime factor in 9% of accidents. Of these, just over half occurred when both the temperature was low (<10C) and humidity high (>80%).

    Hybrid II and Hybrid III dummy headforms gave better repeatability than the rigid aluminium and wooden headforms used in current standards, whilst a novel Bi-mass Hybrid headform gave the most realistic injury prediction.

    When correlating injury severity against test parameters HIC was the most accurate, followed by skull-brain relative linear and rotational acceleration, brain rotational acceleration and skull linear acceleration (all as measured by the BI-mass headform) and resultant linear and rotational acceleration (as measured by a rigid headform). Analysis predicted that AIS 2 injuries would be sustained at HIC 1000, 80g peak relative linear acceleration (150g peak linear acceleration with a metal headform) and 35,000 rad/s/s peak relative rotational acceleration. The initial chin strap load in retention tests should be specified and, if assessed, helmet noise should be measured at the ear and sound attenuation over a range of frequencies.

    If a new helmet specification and demonstrator, based on these findings, was adopted, then new helmet designs should be able to absorb twice as much energy and reduce rotational acceleration by around 50%. This could reduce fatal and serious head injuries by at least 20%.

    The need for chin guard and oblique impact drop tests in standards was verified and proposals submitted to amend the UN ECE helmet regulation. Further work on the oblique impact test and an alternative method adopted in the regulation suggests that whilst the alternative is not as representative, the limits set for the alternative method are closer to typical test results than those set for the oblique impact drop test.