With time seat belt use became much more prevalent in US. At that point depowered airbags were allowed and they rapidly became common place (due to the attention created from the deaths and injuries caused my the prior systems - of which there were few around 200 at that time, vastly out numbered by those benefited) and practically no cost difference. That brought US and EU airbags more in line, but there was still a critical difference. The US airbags were often larger. It was not all about preventing the ejection of an unbelted occupant though. Another consideration was the front middle seat occupant (most often a child with only a lap belt at best) which was still common due to non-extended cab pickups and family/luxury cars with a front bench seat.

Which now brings me to advanced frontal airbags which are now required in US in entire passenger and light truck fleet for just over nine years. Essentially the minimum is that the system calculates occupant weight to determine if the airbag will be prevented from deploying. There is moreover a requirement that the SRS warning label state that an advanced airbag system is in place (with specific clear wording) and also an indicator light (also specifically clearly labeled) indication when the passenger front airbag is disabled. It is very common for the advanced frontal airbag system to also take into account factors such as collision forces and whether the occupant is belted or not in deciding whether to deploy the airbag or not. There are now also systems in place that in addition to all of that also take into account individual seat and spool positions. More over dual igniter systems are becoming more common place, so that front airbag can be inflated more rapidly (though more forcefully) only if needed. In addition multi-stage and variable output air bag systems are permitted in US as well, though they are rarer and typically in more costly cars.

So it really is becoming that US regulations are coming more in line to that of EU and with time and further tweaking of the regs it will become a moot difference - the airbags will be very smart and only deploy most forcefully only when safe and most necessary. Along the way there were many benefits. The US regs are not stagnant nor created in a vacuum as some seem to think. There was history, market forces, and data to what took place and when. Here is one further benefit to the US system that not many people expect: Over time the rules were in fact different across Europe regarding air bags. For example Spain's requirements were slightly different from France's at different times and what happens when you bring that car into Poland and sell it? What about if you bring an older Polish car and sell it in Spain or France, oh boy! There are a number of differences that fall under the US advanced airbag umbrella all handled differently in those three countries at different times, for example in what is permitted regarding the switch based on weight vs. a physical switch and if the seat belt is latched or not to how this is all indicated and labeled. It's a real mess. In US, you just flip the sun visor down and read what you have. Even the procedure for after market alteration specifies that that warning label must be amended appropriately - and how that is to be worded is very specifically laid-out. It's quite impressive to me actually how well this all was thought-out.

Now as to the article. It's not a very good article really. Here's the paper itself (pdf):

http://deepblue.lib.umich.edu/bitstream/handle/2027.42/11297...

I've read through parts and I'll not touch the issue of how it relates to TTIP, but really it shows both in some ways how some EU regs are seeming better and how some US regs as well are seemingly better when you examine crashes statistically. Of course there is not nearly as much raw data for example in the headlight example (you can read the paper itself for details, essentially they had to cull the data down to one hour in one month per each territory and that effects confidence in the result). But to my eyes it really is not all that damning for the US airbag system. The worst results are for high speed driver side front/side airbag deployments (which are difficult to begin with) but when I read through I am not convinced it is factoring all differences from region to region sufficiently to have such a strong claim. For example it's only more recently that advanced airbags were introduced and the early systems were cruder than the current commonly used systems. Cars tend to stay on the road longer in US than EU (particularly in the regions without inspections where my further points will hold as well) so there were many cars with cruder SRS in place. There are many rural areas in those places the roads are not illuminated, there is oncoming and side traffic, wild-life, and people travel are high speed. Further there are more higher GVW cars on the roads in US which could affect the side impact statistics largely to the extent highlighted in my opinion. Notice how well the US does in rollover, that's largely because the market here is different and so it was addressed because there were more cars more prone to roll overs and more people were suffering. So I read over the paper and I personally do not yet believe it controlled for the differences in territories sufficiently.

That said, it's an excellent paper with some surprising results. What I take away from it is really it is a further impetus to move the advanced airbag systems in place in US farther to the higher tech and at least dual-mode operation across the entire fleet. You will never be able to fully address the belted vs. unbelted completely in US simply for practical reasons like people using light trucks in a manner where they back or egress the vehicle often so it's good to still account for it intelligently. Also it would seem wise for the EU to investigate US illumination requirements as they pertain to pedestrian safety cause the results were tantalizing there (though possibly not controlled well enough as well as lacking sufficient data) in the same way that I would hope that US is investigating autodipping intelligent headlights now.