Are truck and Semi Laws in the US good enough?

On Monday January 16th, 2012 there was a BMW rear-ended in on a SoCal bridge north of Santa Barbara, California. The accident was recreated on the news, proposing that the truck had hit the car from behind afterwards the truck had veered off the road and plunged into the ravine below. The driver was killed after it had burst into flames. The BMW, however, was left to sit precariously on the edge of the bridge after breaking through part of the concrete barrier. The three individuals in the car, a mother and her two kids, were eventually rescued from the vehicle from a combination of rescue workers and passerbys with the equipment that was needed.

From 1997 to 2000, I lived in Tervuren, Belgium due to my father's opportunity to work overseas and much of the laws (many of them my mother has told me about the after the fact). These include seat belt laws, semi-trailer truck laws, and driving and drinking laws. The seat belt laws are much more ridgid then many of the laws in the states. At the same time it is one of the laws that becomes difficult to enforce, except when stopping a person for another law.

It's compulsory to wear a seat belt (ceinture de sécurité/autogordel), including in the back seats if belts are fitted. It is the driver's responsibility to ensure all passengers wear their belts (and the driver will be fined if passengers are not belted in).

There were also certain 'etiquette laws' , particularly involving semis. My mother has told me that in Europe semis included: not pass cars (sedans, vans, etc), drive on the left (like all traffic there), and general courtesy to the other drivers of the road. Other laws included that passing on the right is illegal (meaning switching lanes with the purpose of passing a car) and only moving into the left lane when passing another car, or in the case of semi-trailer trucks another semi. In addition this many of the drunk driving laws in Europe have zero tolerance along with steep fines. Along with that the limit is much lower than other countries in the area (such as the UK (including Scotland, England, and Wales). Consequences for going over the limit can include a 5 year licence suspension and six months in jail along with the large fines. The question that I've found most disconcerting for in the United States drunk driving laws, is why are there individuals who have more than one DWI or DUI and what can we do to increase the laws against drunk driving?

Questions:
Are current traffic laws protecting people from fatal accidents?
How much does distracted driving impair our ability to drive safely (including but not limited to drink holders, talking on the phone, passenger interaction, etc.)?
Are the laws against drunk driving serious enough?
Should semi-trailer truck laws be reassessed?
Are there any laws which protect the semi-trailer truck drivers?
How much is the commercial industry pressuring semi-truck trailer drivers to take on unreasonably long hauls without proper rest?

Resources: Driving in Belgium, Driving in Europe, Road Rules and Driving in Belgium, Driving Laws in Belgium, SADD Statistics, MADD Statistics, Drunk Driving Accident Statistics, Drunk Driving Fatalities