Background
Whether during normal operations of a vehicle or crash type circumstances, the protection and containment of a vehicle's occupants offers many engineering challenges, some of which are controversial. While containment problems dealing with automobiles have gotten the most attention among vehicles, the same issues can be addressed in recreational boats, personal watercraft, and construction and agricultural equipment. Miller Engineering has addressed several of these topics in our research and consultations.
Recreational Boats:
Boat Occupant Ejection: One of the leading causes of drownings relative to boats originates from persons being thrown overboard or falling out of a boat in motion. Besides these "ejection" types of accidents, persons also have falls getting into and out of boats and dockage and while moving within a boat while it is in motion. Some of these types of accidents also result in a person unexpectedly ending up in the water.
Miller Engineering completed a multi year contract with the US Coast Guard through the American Boating and Yachting Council (ABYC) to investigate these phenomena. An overview of the various boating topics dealing with occupant protection appeared in the report:
Miller, J.M., Main, B.W., Iqball, C.S. and Grieser, B.C. (September, 1994). "Occupant Protection in Recreational Boating", Final Report to U.S. Coast Guard.
The issues specific to bow rider boats involve persons seated in front of the driver of a boat in an open area in the far front. This location is subject to slightly more motion while the boat moves forward. Hitting or crossing large waves would naturally cause passengers in this location to experience more motion than those in different locations. The amount of motion experienced can be judged in part by the accelerations which a typical passenger might feel. The quantified size of these accelerations was measured by Miller Engineering in an early experiment using real boats under real wake crossing conditions. This is reported on in:
Wiker, S.F. and Miller, J.M. (1983). Acceleration Exposures in Forward Seating Areas of Bowrider Recreational Boats. Human Factors, 25 (3), 319-328.
This area was further explored relative to the tendency for a person to be ejected from the bow-rider area as a function of the height of the seat backs within bow rider boats. Further testing was done to determine what seat back heights would improve the containment of persons seated in this area and reduce the tendency for ejections. Again, using real boats under real operating conditions, data were collected and the results provided in these three reports:
Miller, J.M., Grieser, B.C. (August 1998). "Bowrider Backrest Height Variables: An Experimental and Simulation Study, Part II" Occupant Protection Phase III, Final Report to U.S. Coast Guard.
Miller, J.M., Grieser, B.C., Clark, D.R. (February 1996). "Bowrider Backrest Height Variables: An Experimental and Simulation Study," DOTCG Grant No. 130202, NTIS PB96 195839XSP, Final Report to U.S. Coast Guard.
Miller, J.M., Grieser, B.C., Clark, D.R. (February 1996 ). "Experimental Determination of Lateral Boat Accelerations During Turns at Bow Seat Versus Stern Seat Locations," DOTCG Grant No. 130202, NTIS PB96 195839XSP, Final Report to U.S. Coast Guard.
Boat Slips and Falls and Climbing: Another key to occupant containment in boats is for passengers to have the ability to move in, out and about a boat using adequate, effective handholds. Numerous current model boats were reviewed relative to handhold availability. Two areas which Miller Engineering undertook special projects in were with respect to Boat Handholds and Boarding Ladders. The results of our studies in this area are presented in the following three papers:
Miller, J.M., Grieser, B.C. (July 1998). "Boat Handhold Placement" Occupant Protection Phase III, Final Report to U.S. Coast Guard.
Miller, J.M., Grieser, B.C. (June 1998). "Boat Boarding Ladder Placement" Occupant Protection Phase III, Final Report to U.S. Coast Guard.
Miller, J.M., Grieser, B.C., Clark, D.R. ( April 1996). "Designs of Boat Handholds and Boarding Ladders: Principles and Examples," DOTCG Grant No. 130202, NTIS PB96 195839XSP, Final Report to U.S. Coast Guard.
Automobile Restraint Systems
Infant Carriers/Child Car Seats: State laws typically require infants to be contained in car seats and Federal/Consensual standards establish criteria which qualifying car seats must pass. Specific features of some manufacturers' car seat models have resulted in mandatory or voluntary notifications and recalls by the CPSC. A different aspect of this issue is the interaction of products labeled as "infant carriers" which are not intended and should never be used for child restraint in a car. The difficulty which manufacturers and retailers have had is the education of the public who present themselves to buy such a product for their child, grandchild, or fried's child (such as for a present). While a child seat my cost $50 , the lighter usage infant car carrier may cost only $25, leading persons to the lower price. Because they appear to serve the similar function of carrying a child, they may be very similar in appearance. Miller Engineering researched these two products to find that to the lay purchaser, they may appear so similar that they cannot be distinguished from their features. When this is the case, warnings relative to their proper intended use are essential, both at the point of sale and on the products themselves. this issue has been explored in our publication "Communicating a Safety-Critical Limitation of an Infant Carrying Product," the specific location of which appears in our website location: Publications by Complete Citation-
Adult Occupant Protection and Passive Restraints in Autos
In the area of automobile occupant protection Dr. Lehto from Miller Engineering and Purdue University has undertaken numerous studies in this area, both laboratory and statistical. These include studies addressing general passive restraint systems, concealed air-belt systems,lap belt usage on 2 point motorized belt systems. Dr. Lehto holds at least one patent in this area Articles which address these topics wherein Dr. Lehto is our primary expert follows:
Lehto, M.R. and Foley, J.P. (1993). "Physical Aspects of Car Design: Occupant Protection," Automotive Ergonomics, Chapter 7, Peacock, B. and Karwowski, W. (eds.), Taylor and Francis, pp. 141-160.
Lehto, M.R. (1988). An Interdisciplinary Scheme for the Design and Evaluation of Automotive Passive Restraint Systems, Phase II, Final Report presented to General Motors.
Lehto, M.R. and James, D., "Safety Knowledge of Users and Non-users of the Lap Belt on 2-Point Motorized Belt Systems," working paper.
Lehto, M.R. and Foley, J.P., "Design and Development of a Concealed Air Belt System for Protection of Automobile Occupants," working paper.
Lehto, M.R. and Foley, J.P., "Physical Aspects of Car Design: Occupant Protection," Chapter 7 in Automotive Ergonomics, Peacock, B. and Karwowski, W. (eds), Taylor and Francis, 1993, pp. 141-160.
Lehto, M.R., An Interdisciplinary Scheme for the Design & Evaluation of Automotive Passive Restraint Systems, Technical Report presented to General Motors and the American Society for Engineering Education, 1987.