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Differences and standards prescribe retrofit options

By Matthew A. Daecher

My last column [BUSRide, January-February 2010, Risk Management] focused on the decision many operators could soon face with regard to retrofitting seatbelts to the existing fleet. Such a decision will ultimately come down to several factors that include cost, restraint capabilities, customer demand and risk.

Going off the assumption that many operators may retrofit a portion of their existing fleet, they will have to take several factors into consideration to determine the type of restraint system to install.

Choices in protection
Assuming a coach is capable of a retrofit, an operator may choose either a two-point (lap belt only) or three-point system (lap and shoulder belt). Retrofit capability may be limited by the age of the coach and even preclude restraint system retrofitting whatsoever.

There is no argument that a three-point system provides the greatest protection from injury in various crash scenarios. Injury data taken from the National Highway Traffic Safety Administration (NHTSA) Motorcoach Sled Test Program report of October 2008 confirms this and led to the forthcoming three-point system requirement for newly manufactured coaches.

Nonetheless, most operators will find the cost of retrofitting a three-point system cost prohibitive without the availability of dedicated government funding grants. Hence, an examination of the benefits of a two-point system versus the current no-belt system is relevant.

The NHTSA sled tests that indicate three-point restraint systems provide superior protection also revealed that two-point belt systems provide little to no advantage over non-equipped coaches in the forward crash test scenarios. Average male and female crash dummies restrained by two-point restraint systems had more significant neck and head injuries than the unrestrained crash dummies. Two-point restraint systems kept crash dummies mostly in their seats, while unrestrained crash dummies often ended up on the floor and in the aisle.

With data only available on forward crash scenarios, and no detailed information on any subsequent injuries resulting from unrestrained occupants not remaining in the seats, many operators may choose to not retrofit their coaches. Add to the mix that injuries of belted occupants were often more severe if unbelted passengers were seated behind them, and there is even more uncertainty as to retrofitting with two-point systems.

The structural requirements of two and three-point restraint systems determine the significant cost differences. The two-point systems that some coach and seat manufacturers offer are designed for use in conjunction with existing coach and seat structures. In some cases the operators may be able to install these lap belt systems which are essentially attached to the existing seats.

On the other hand, in most cases the three-point system retrofits will require the replacement of all passenger seats, and reinforcement at floorboard and sidewall seat attachment points. Considering the extent of the structural changes, these retrofits will require the work of the coach manufacturers.

Standards to consider
Many products are currently available to operators interested in retrofitting their coaches — some certainly better than others. The products from coach and seat manufacturers are likely to have gone through extensive testing to meet some established standards, which is important for product liability claims. The same is true for operators who may someday face questions in a lawsuit pertaining to the products they chose to retrofit their coach.

Aftermarket manufactured products may very well meet the same standards — or they may not. In which case, to make the wisest choice of retrofit products operators must understand the applicable standards.

The Federal Motor Vehicle Safety Standards (FMVSS) are standards required of newly manufactured vehicles and installed components. All seatbelt assemblies and anchorages must meet all applicable FMVSS that cover the performance, strength and placement of belt restraint system components, regardless of whether the vehicle is a Ford Mustang or a Prevost H3-45.

The following list indicates the currently applicable FMVSS:

  • FMVSS 208 Occupant Restraint Systems (currently applies to driver seat only)
  • FMVSS 209 Seat Belt Assemblies (Belts and Hardware)
  • FMVSS 210 Seat Belt Assemblies and Anchorages (Assembly Anchorage Points)

Any operator who purchases a retrofit restraint system should ensure its total compliance with these FMVSS standards. Any belt and anchorage assembly should comply with FMVSS 209 and 210 when installed, and compliance with FMVSS 208, though only currently applicable to the driver seat, would indicate a well thought out and tested product.

Some coach restraint system manufacturers are also complying with other FMVSS requirements.  For instance, FMVSS 207 applies to the actual performance of the seats equipped with a restraining device — even though as the standard exists now it specifically exempts bus seats. FMVSS 222 concerns bus seating, crash protection and seat loading for school buses only, where there are no seatbelt requirements (think compartmentalization).

While neither of these standards currently applies to motorcoaches, operators should look favorably on the products that meet additional standards. They also should know if the system they choose meets one of the established crash pulse standards.

Without getting too technical, the crash pulse is the rate of deceleration; a multiple of the acceleration due to gravity denoted as g.

In the U.S., passenger car seat belt systems must be able to withstand a 20g deceleration force. In the European Union (EU) and Australia, where restraint systems are required on coaches, deceleration standards for coaches are 6.6g and 20g respectively. While there most certainly will be a U.S. standard issued with the new coach restraint system requirements, it remains uncertain as to whether performance standards for existing coaches retrofitted with seat belts will be established.

The EU and Australia restraint regulations established retrofit standards, but as yet there is no indication this will be the case in the U.S. In the EU, operators retrofitting coaches had to meet the 6.6g standard with their retrofitted restraint systems. In Australia, retrofitted coaches had to meet a 10g standard. It is worth noting the bus and coach industry in both the EU and Australia faced many of the same questions and concerns that we face in this country, especially with regard to coach construction issues and additional loads.

It would be easiest on operators if the federal government announced retrofit standards for passenger restraint systems along with the forthcoming U.S. OEM standards.  However, if this does not happen, operators should install retrofit systems that at least meet the 6.6g standard. All indications are many of the retrofit systems currently offered by coach and seat manufacturers meet this standard.

From a risk management perspective, any decision coach operators make regarding a retrofit must focus on the potential they will have to answer questions pertaining to their selection process. Using the existing and historical standards as a guide easily provides the rational basis for choosing a particular system.

Matthew A. Daecher is president and CEO of Daecher Consulting Group, Inc., Camp Hills, CA.

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Posted by on Feb 1 2010. Filed under Risk, Safety. You can follow any responses to this entry through the RSS 2.0. You can leave a response or trackback to this entry

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