Licensed Professional Engineers

FORENSIC CLUES # 28.5 - "Yamaha Rhino UTV Accidents " by John L. Ryan

FORENSIC CLUES -A newsletter dedicated to keeping attorneys informed of the technical side of product liability cases.

Volume 28.5 October/November 2008

“Yamaha Rhino UTV Accidents”

By John L. Ryan

UTV Accidents

The Yamaha Rhino is one of many different brands of utility vehicles on the market today. Utility vehicles, or UTV’s as they are referred to, are all-terrain vehicles with seating for at least two people, as well as a cargo bed. These vehicles are popular among many different types of users, from hunters to farmers to outdoor enthusiasts. Most of these UTV’s come equipped with standard roll over protective structures (ROPS) and seatbelts. This is a vast improvement over all-terrain vehicle designs that lack roll over protection, resulting in numerous rollover fatalities and injuries every year. Unfortunately, there are still problems with some of the UTV’s on the market.


Rhino UTV accidents appear to be getting the most attention from the media, with numerous ads on television and the internet of attorneys looking to represent people involved in Rhino accident cases.

UTV Center of Gravity testing

The Yamaha Rhino is purported to have a high center of gravity and a narrow wheelbase, making it susceptible to low speed overturn accidents.

What Happens in Accidents

Accidents occur when the UTV overturns, usually during low to moderate speed turns. The driver and/or occupants who are injured in these overturns get crushed by the vehicle or ROPS structure. Some drivers and passengers do not wear the supplied seatbelts, and get partially or completely thrown out of the UTV and crushed in the process. Even occupants who wear their seatbelts, however, continue to get injuries during these overturns. The ROPS and seatbelt help protect the occupants from fatal injuries, but the lack of doors on the UTV has proven to result in unnecessary injuries. Drivers and passengers arms and/or legs fall outside of the perimeter of the vehicle during overturns. These legs and arms are then crushed by the overturning UTV.

What Does Yamaha Say?

Yamaha has been slow to respond to the claims of injuries and overturning Rhino’s. Yamaha sent Rhino owners a letter dated September 11, 2006. This letter warns users to make sure to use their seat belts, and warns that the Rhino, like any other off-road vehicle, can overturn in certain circumstances. The letter continues by warning drivers and passengers to not attempt to prevent the overturn by putting an arm or leg outside of the vehicle. Yamaha then discusses new warning labels that they supplied to Rhino owners. Yamaha released a technical bulletin on August 23, 2007 to Rhino dealers. This technical bulletin discusses new add-on features for the Rhino, including “doors”, passenger handholds, and warning labels. The technical bulletin instructs Rhino dealers to install these features on any 2004-2007 Rhinos in stock. The bulletin also recommends that current Rhino owners get these modifications added to their vehicles, at no cost to the owner. On August 27, 2007, Yamaha sent a letter to registered Rhino owners detailing the new modifications and informing them that they could have these modifications made free of charge. Copies of these documents can be obtained from Safety Engineering Resources free of charge, just call (479) 549-4860, or email us at This documentation by the manufacturer shows the extent of the problem of Rhino overturns and resulting injuries. Yamaha has failed to issue a true recall that would ensure that UTV’s in use would be equipped with the modifications.

The Design Process

The American Society of Mechanical Engineers and the National Safety Council agree on design principles that should be used to ensure that product hazards do not cause injury to product users.

Hazard control should be accomplished in a planned, controlled manner. This design hierarchy calls for eliminating any product hazards at the design level when this is possible. If a product has inherent hazards that cannot be completely eliminated, then guarding must be used to protect the product user from the hazard. Only when guarding falls short of offering protection, properly designed warnings should be used to help product users to avoid the hazards. If it is impossible to eliminate the hazard, guard the hazard, or warn of the hazard, user training may or may not help control user behavior to minimize accidents. Personal protective equipment such as hard hats, goggles, ear protection, etc. should never be relied on as a primary form of hazard protection because people cannot be relied on to consistently wear the protective equipment.

What Could be Done?

Following the design process outlined by the National Safety Council, the best solution to a hazard is to eliminate it out of the product. With a UTV there are multiple design elements that can make them susceptible to overturns. The lack of a rear differential makes ATV’s and UTV’s harder to control and more susceptible to overturns. A differential turns the wheels on an axle at different speeds, which is what automobiles use to make turning without sliding possible. When a vehicle without a rear differential turns, rear driven wheels will attempt to push the vehicle forward instead of following the turn that is being initiated by the steering wheel.

Another factor which some are claiming is the cause of the Rhino’s tendency to overturn is a high center of gravity combined with a narrow wheelbase. The higher the center of gravity is, and the narrower the width of the vehicle is, the greater the likelihood is for the vehicle to overturn. A vehicle with a high center of gravity can overturn when it hits a bump or hole whereas a vehicle with a lower center of gravity will require much greater forces to overturn. The height of the center of gravity is affected by the weight distribution of the vehicle. The more weight that is put lower on the vehicle, the lower the center of gravity will be. The weight distribution of the vehicle is controlled by the design of the vehicle structure, location of the engine, material used, ground clearance, and other factors. The height of the seats affects the center of gravity, as does the height of the bed of the UTV. What gets put in the seats and bed can have a huge impact on the center of gravity, particularly since the beds of the UTV’s are located relatively high. The width of the vehicle also affects stability. Think of a motorcycle with one wheel per axle. A motorcycle can be easily pushed over by hand. A vehicle with two wheels per axle is less likely to overturn, and the distance between the wheels affects the stability of the vehicle. Yamaha could minimize the risk of overturns by adjusting these variables to provide maximum stability.

When a hazard cannot be completely eliminated by design, the hazard must be neutralized with guarding. Yamaha and other UTV manufacturers have begun this process by using roll over protection and seatbelts. The critical element in ROPS use is keeping the people within the safety provided by the frame of the ROPS and vehicle. Using the seatbelt will help this, and interlocking the seatbelts so that they must be worn to start the vehicle will help ensure that UTV owners will use the seatbelt. This technology has been in use since the early 1970’s. Doors are also necessary to ensure that vehicle occupants are retained in the perimeter of the vehicle in an overturn. Yamaha’s add-on “doors” may help keep legs inside the vehicle, but will not protect occupants’ arms. Other manufacturers provide more complete doors that help keep occupants within the protection of the ROPS and vehicle frame.

Update!: CPSC Recall March 31, 2009

The CPSC announced on March 31, 2009, that users of Yamaha Rhinos should stop using the vehicles immediately until repairs are made by a local dealer. The CPSC investigation of the Rhino found that many of the rollover related deaths and injuries involve low speed turns on level terrain. Yamaha has volunteered to suspend sales of Rhinos until repairs can be made. The CPSC notice is shown below:

Yamaha states that this is not a recall, but a “voluntary repair program”. Yamaha states on its webpage

“According to the CPSC, the following two repairs are needed “to help reduce the chance of rollover and improve vehicle handling”:

  • Installation of a spacer on each of the rear wheels.
  • Removal of the rear anti-sway bar. “

This is further evidence of the hazardousness of the Yamaha Rhino and proof that the Rhino is unreasonably dangerous due to its propensity to overturn at low speeds and on level surfaces. The repairs are needed to reduce the likelihood of overturns. The CPSC notice and Yamaha’s repairs are consistent with Safety Engineering Resources’ findings on the Rhino’s tendency to overturn under normal operating conditions.


Safety Engineering Resources—  

Safety Engineering Resources provides full service engineering consulting services, including product testing and analysis and expert witness services. We are working on several UTV cases now, give us call to discuss a case or potential case that you have. (479) 549-4860

©2008 Safety Engineering Resources

(479) 549-4860