Okay, First off, I never said I was the world expert. This kind of remark from you tells me that you are sick of my posts and are taking it out on me in a petty way. You don't like that I post about things I know or maybe you just don't like me, and that's fine, but I do help people and that's why I do these things.
The FMVSS. There are of course safety standards that car manufactures follow for seat belt safety. I stated that there are safety standards that car manufacturers use in my original post. Are you saying this is false and I made this up? Just because I don't ALWAYS put the encyclopedia does not make my statements false.
Secondly, Steel makes things far safer than wood, and it's known fact that for a seat belt to work properly it needs to be mounted directly or indirectly to the frame of the vehicle. This is common knowledge but also I stated this because it's in the FMVSS Regulation. Not something I made up. Seat belts are like the phrase, "You're only as strong as the weakest link". If you cannot comprehend this simple construct, I cannot help you. If something is in that chain is weak such as wood, guess what, your seat belts that hold you stationary are limited to that wood. The industry is not using Titanium, (It can be softer than steel in some cases) they are using steel mounts and in some cases steel wire bolted directly to the floor. These are well established facts. Not made up items by me.
So because you called me out. I didn't want to have to do this, but here is the Code of Federal regulations with summaries for lamens to understand. I post the actual code, and I present a summary for those who don't speak legalise. I bold underline the important statistics and facts in case you don't want to see the whole wall of text.
Regarding seat belt Anchorage:
Code of federal regulations:
571.210 Standard No. 210, Seat belt assembly
anchorages.
S1. Purpose and scope. This standard establishes requirements for seat belt assembly anchorages to insure their proper location for effective occupant restraint and to
reduce the likelihood of their FAILURE.
Summary: This means the purpose of this regulation is to
reduce failure with the process of the belt and mounting.
S2. Application. This standard applies to passenger cars, multipurpose passenger vehicles, trucks, buses, and
school buses.
Summary: School Buses are included.
S3. Showing school bus application only here:
School bus torso belt adjusted height:
Means the vertical height above the seating reference point (SgRP) of the horizontal plane containing a segment of the torso belt centerline located 25 mm to 75 mm forward of the torso belt height adjuster device, when the torso belt retractor is locked and the torso belt is pulled away from the seat back by applying
a 20 N horizontal force in the forward direction through the webbing at a location 100 mm or more forward of the adjustment device as shown in Figure 5.
Summary of S3 Belt Adjusted Height: The belt mechanism needs to survive materially
20 N which is newtons or newton meters. So this answers the mounting questions regarding
strength of anchoring the belt. IF anywhere in the chain of the mounting to the frame it's less than 20 Newtons, it's not considered safe federally.
A 1/8th inch steel bar requires roughly 68.3 Newtons to bend. Which is width of a chair railing. So a 1/8th inch steel bar which is thin provides nearly
3.5 times the required federal Strength. Pine which is commonly used can have as low as
3 Newtons of force to break at the lowest, and up to as
high as steel depending on using a harder wood, or compressed manufactured wood, but wood has different properties and is
threaded by nature and results can very greatly.
Hence don't use wood. Even bad steel with impurities due to it's properties can maintain close to it's 68 N rating at that thickness and will be over the required 20 N. Follow the height to torso values listed above.
School bus torso belt anchor point:
The midpoint of the torso belt width where the torso belt first contacts the uppermost torso belt anchorage. Seat belt anchorage means any component, other than the webbing or straps, involved in
transferring seat belt loads to the
VEHICLE STRUCTURE, including, but not limited to, the
attachment hardware, seat frames, seat pedestals, THE VEHICLE STRUCTURE ITSELF, and any part of the vehicle whose FAILURE CAUSES SEPARATION OF THE BELT FROM THE VEHICLE STRUCTURE.
Summary: Pretty much exactly what I stated in my first post.
"Designated seating position" means:
Part 1: (omitted as it only covers vehicles less than 10k GVWR)
Part 2:For vehicles manufactured on and after September 1, 2011, designated seating position means a seat location that has a seating surface width, as described in § 571.10(c) of this part, of at least 330 mm (13 inches). The number of designated seating positions at a seat location is determined according to the procedure set forth in § 571.10(b) of this part.
However, for trucks and multipurpose passenger vehicles with a gross vehicle weight rating greater than 10,000 lbs, police vehicles as defined in S7 of FMVSS No. 208, firefighting vehicles, ambulances, and motor homes, a seating location that is labeled in accordance with S4.4 of FMVSS No. 207 will not be considered a designated seating position. For the sole purpose of determining the classification of any vehicle sold or introduced into
interstate commerce for purposes that include carrying students to and from school or related events, any location in such a vehicle intended for securement of an occupied wheelchair during vehicle operation
is regarded as four designated seating positions.
Summary of what Part2 is stating here. If vehicle is over 10k GVWR, S4.4 of FMVSS No. 207 will
NOT be considered a legal designated seating position. Also most of our buses are still considered commercial vehicles so the Interstate commerce line there applies to us. So belts are not even
LEGALLY REQUIRED on the SCHOOL BUS!!! Unless your bus is a tiny bus under 10k. Sorry shorty bros in this category

This is why children get on school buses every day on buses without belts. So by adding seat belts and mounting them to
steel which is mounted to the vehicle structure, you are doing your family a solid and already improving the situation making them safe.
So I was right, and I didn't make it up. I just didn't go into depth previously, so please stop acting like I don't know what I'm talking about. I simplify things sometimes so regular people who don't want to go read the Regulations can go about their business. I'm not introducing anything unsafe to people.
I also don't post on posts I know nothing about or I state that I don't know at the beginning of the post and self label things as speculation to provoke thought. But if I don't put that header on my posts, going forward you will assume I know what I'm talking about.