Note: This article summarizes research from several of Technology Associates’ peer reviewed journal articles cited here:

Seluga, K., Baker, L., & Ojalvo, I., “A Parametric Study of Golf Car and Personal Transport Vehicle Braking Stability,” J Accident Analysis & Prevention 2009; 41:4:839-848.

Seluga, K., Long, T., “Analysis and Prevention of Child Ejections from Golf Cars and Personal Transport Vehicles”, 21st International Technical Conference on the Enhanced Safety of Vehicles (ESV), Paper #09-0186, June 2009.

Seluga, K., & Ojalvo, I., “Braking Hazards of Golf Cars and Low Speed Vehicles,” J Accident Analysis & Prevention 2006; 38:6:1151-1156.

Seluga, K., Ojalvo, I. & Obert, R., “Low Speed Vehicle Passenger Ejection Restraint Effectiveness,” J Accident Analysis & Prevention 2005; 37:4:801-806.

According to the Consumer Products Safety Commission (CPSC), there are approximately 15,000 golf car related injuries requiring emergency room treatment in the US each year.

One significant mode of injury in golf car accidents is passenger ejection, which can lead to serious injuries, especially of the head. Based on CPSC statistics, roughly 40% of golf car accidents involve a person falling out of the car, and many of these accidents involve young children. In addition to ejection accidents, approximately 10% of golf car accidents involve a rollover and statistics indicate that such accidents are roughly twice as likely to lead to injuries requiring a hospital stay as non-rollover accidents.

Passenger Ejections

One common scenario for a passenger ejection accident occurs when a car, traveling near its maximum speed, is turned sharply to the left. During a sharp left turn, centrifugal acceleration forces tend to force the passenger to his right, which can lead to ejection. Sharp turns are less likely to lead to a driver ejection because the driver has the steering wheel to hold onto and can always anticipate when he is about to initiate a turn.

Golf cars (when used on golf courses) are typically not equipped with seatbelts because of their need to allow passengers to enter and exit the vehicle frequently with ease. Therefore, the ANSI (American National Standards Institute) golf car safety standard, Z130.1, does not require seatbelts for golf cars. As a result, it is necessary to equip golf cars with passive restraints that will protect unbelted passengers from ejection. In place of seatbelts, golf car standards require readily accessible handholds and body restraints that prevent the occupants from sliding to the outside of the vehicle. As a result, golf cars are typically designed with rectangular or semicircular bars that rise up from each side of the car’s bench seat and are designed to serve as both handholds and hip restraints. One of the deficiencies of this design is that the location of the handhold (i.e. at the outboard edge of the seat) is also the fulcrum about which an ejected passenger will tend to rotate. Therefore, this type of handhold, even when used, does not provide the passenger sufficient leverage to prevent ejection. Another possible deficiency is that the side restraint is often not large enough to prevent ejections.

Technology Associates has performed biomechanical simulations of golf car passenger ejections using the Articulated Total Body (ATB) software to evaluate the effectiveness of existing hip restraints. This research indicates that many of the hip restraint configurations currently installed on golf cars, which can be as short as 3-4”, are not adequate to prevent passenger ejection during a sharp turn at high speed. However, restraint design improvements, such as the addition of a centrally mounted handhold, can be easily provided and would greatly reduce the likelihood of passenger ejection without interfering with convenient entry and exit from the passenger side of the seat.

Child Ejections and Seatbelts

CPSC injury statistics indicate that approximately 40% of all golf car related accidents involve children (i.e. age < 16) and 50% of these involve a fall from a moving car. As a result, children represent a dramatically large portion of all ejection accident victims.

These statistics include the class of vehicles officially categorized as Personal Transport Vehicles (PTV's), which are golf cart style vehicles used at locations other than golf courses.

Since there are currently no occupant restrictions or seatbelt requirements for these vehicles set forth in the applicable ANSI safety standards or manufacturers’ operator’s manuals, young children of any age are often permitted to ride in open, off-road vehicles that are capable of traveling up to 20 mph on flat ground and are not equipped with seatbelts. The results of this practice are headlines like the ones listed here:

Child dies in golf cart accident: "An 8-year-old girl...died Sunday after falling from a golf cart two days earlier..." The Neshoba Democrat, September 07, 2005

Volunteer, 15, Dies Days After Golf Cart Fall: "A boy, 15, from West Covina died several days after falling off a golf cart while doing volunteer work at a Long Beach festival..." cbs2.com, Aug 5, 2007

Prayers, support strengthened family of boy hurt in fall from golf cart: "Shawn, 9, had undergone brain surgery for a severe head injury he received when he fell off the back of a golf cart in which he was riding..." The Eagle Tribune, November 14, 2007

14-Year-Old Dies After Fall From Golf Cart: "Haley was a passenger in the golf cart and fell out when it went around the corner...", WYFF4.com, January 21, 2008

12-year-old boy dies in golf cart crash: "A 12-year-old boy... has died after being thrown from a golf cart driven by his father" Las Vegas Sun, Sep 8, 2008.

Child injured after being run over by golf cart: "Fonville fell out, and was then run over by the cart..." News-Leader.com, July 18, 2009

Teenager hurt after falling out of golf cart: "A 13-year-old girl from Columbia, Ill., suffered serious injuries Saturday after she fell out of a golf cart and hit her head on the road..." News-Leader.com, August 16, 2009

Hoover boy dies from injury in fall from golf cart: "A 15-year-old Hoover boy died Sunday from injuries he received after falling from a golf cart..." The Birmingham News, March 22, 2010

Golf Cart Head Injury Claims Bella Wiegert, 6: "the family's red, electric cart hit a bump on Chippendale Road and Bella fell out, striking her head on the pavement..." The Ledger, Lakeland, FL, April 26, 2010

Teen boy dies after falling off golf cart: "A 14-year-old Kamuela boy died Thursday... The cart made a sharp left turn into a driveway, and Derego, who was riding in the back, fell off and struck the pavement, police said." Honolulu Star Bulletin, June 5, 2010

Manson boy hurt in golf cart accident: "A 15-year-old Manson boy was flown to a Seattle trauma center Tuesday night after he was thrown from a golf cart and showed signs of a possible skull fracture, authorities said.... He was riding in a golf cart with a friend at the Lake Chelan Municipal Golf Course, when the friend drove down a steep hill near the 18th hole and turned left, causing Lolos to fall out of the cart..." The Wenatchee World, June 23, 2010

Anthropomorphic Hybrid III dummy testing and computer simulation analyses have confirmed that children are especially susceptible to ejection from these vehicles because of their small size, their inability to touch their feet to the floor, and their reliance upon the hip restraint for stability. The same studies have shown that seatbelts are extremely effective in preventing occupant ejection.

The National Golf Car Manufacturers Association (NGCMA) has put forth the opinion that golf cars and PTVs should not have any type of seatbelt system in light of the absence of a rollover protective structure (ROPS), though the National Highway Traffic Safety Administration (NHTSA) has concluded that “the conjecture by some commenters that it would be valuable to be able to jump out of an LSV are unsubstantiated speculation that is especially unpersuasive given the volume of data showing that ejection is extremely dangerous and that seatbelts are remarkably effective at preventing ejection”.

In light of these facts, children should be prohibited from riding in golf cars without a seatbelt type restraint when driven on golf courses and seatbelt type restraints, with ROPS if necessary, should be provided for each occupant, especially children, when driving outside the golf course setting.

Rollovers

Rollovers often occur as a result of a driver losing control of the car while traveling downhill on a car path. One potential source of a downhill loss of control is the current industry practice of manufacturing golf cars with brakes on only the rear axle wheels. It has long been understood that a braked vehicle with skidding rear tires and rolling front tires is directionally unstable but this instability will not always manifest itself when a vehicle is traveling at sufficiently low speeds on level ground. However, besides reducing braking effectiveness (when compared to four wheel braking), rear wheel only brake designs can easily lead to “fishtailing.” Furthermore, the reduced braking effectiveness on downhill slopes can lead the driver to falsely perceive a brake failure, causing him to press harder on the brake pedal, which in turn leads to a locking of the braked wheels and an out-of-control skid. This hazard is aggravated at golf courses that incorporate hilly terrain with steep, narrow golf car paths and sharp turns. Such conditions make it desirable to create golf cars with good braking characteristics for use on courses with downhill slopes of 10 degrees or more.

Industry standards for the design of golf cars contain minimal braking requirements that do not include tests for downhill braking. In addition, there are no widely accepted standards for golf car path design, and inadequate recommendations provided by car manufacturers for maximum path slope and minimum turning radii are ambiguous with warnings that refer to “steep grades” and “sharp turns” without quantifying these terms. This separation between golf car design standards, which only require dynamic braking tests on flat ground, and sloped car path design, which lack any specificity, causes golf cars to be routinely driven on potentially dangerous terrain that is not addressed by the ANSI golf car standard. In addition, while the ANSI standard requires that a golf car’s maximum speed not exceed 15 mph on level ground, that speed can easily be exceeded when traveling downhill.

To evaluate the potential hazards of creating golf cars equipped with brakes on only the rear axle wheels, Technology Associates has analyzed the braking of a two-axle vehicle, equipped with brakes on either or both of its axle wheels. In addition, dynamic two-dimensional simulations of a braking golf car traveling downhill have been created to study vehicle dynamic stability. For this comparison, we introduce the term “braking efficiency”, defined as the actual vehicle braking deceleration, divided by the braking deceleration of the same vehicle with brakes on all four wheels (i.e. the maximum possible braking deceleration for a given slope and coefficient of friction). Thus, by definition, the case with braking on all four wheels yields an efficiency of 100%.

For either case where only the front or rear wheels are braked hard, braking efficiency decreases rapidly as the downhill slope increases, such that at path down slopes over 20 degrees, the brakes are no longer able to prevent the golf car from accelerating downhill. For slopes of 10-15 degrees, with which golf cars must currently contend, placing brakes on only the rear axle wheels provides only 25-37% of the braking that could be achieved with brakes on all four wheels. Therefore, equipping a car with brakes on only the rear wheels reduces the available braking efficiency significantly when compared to a vehicle with brakes on all four wheels.

Dynamic simulations indicate that golf car yaw instability is not likely on flat ground and will not manifest itself during ANSI brake performance testing. However, for a vehicle with brakes on the rear wheels only, when the initial speed is 17 mph or higher, yaw instability can occur when traveling down a 10 degree slope when modest steering inputs are made. Such loss of control could easily cause the car to leave the path and either collide with, or tip over, nearby obstacles and path curbs. However, when the front axle wheels, or all four wheels, are braked hard enough to lock them, there is no significant deviation from straight path travel. Therefore, if the cars were equipped with front brakes (either by themselves only, or in combination with rear brakes) this yaw instability problem would be significantly reduced if not entirely eliminated.