Please read what I wrote. There is no way you actualy did so, and then made that post. Here's a version with smaller words:
1. When a big vehicle hits a small vehicle, the small vehicle usually gets more dented.
2. When two small vehicles crash, there is usually less danger of injury than when two big vehicles crash or when a big vehicle and a little vehicle crash.
3. Vehicles are safer now than they used to be, even though they are generally lighter than they used to be.
Weight does not equal safety. Safety is not a reason to produce unnecessarily heavy cars - especially at the expense of fuel efficiency.
Yeah, well there seems to be some disagreement about that.
US Dept. of Trans.
http://www-nrd.nhtsa.dot.gov/Pubs/808569.PDF
Effect of a 100-pound weight reduction for passenger cars
NHTSA estimates that a 100-pound reduction in the average weight of passenger cars, with
accompanying reductions (based on historical patterns) in other size parameters such as track width,
and in the absence of any compensatory improvements in safety technology, would have a
significant adverse impact on safety:
• Fatalities would increase by an estimated 302, which would be 1.1 percent over the current
level.
• Serious or moderate injuries (AIS 2-6) in nonrollover crashes would increase by 1,823,
which would be 1.6 percent over the current level
• Police-reported 'A' or TC' injuries, which are usually less serious than AIS 2-6 injuries, would
increase by 8,804 in nonrollover crashes, which would be 3.2 percent over the current level.