We often fail to acknowledge the forces which are at play when simply driving your car, even at legal speeds. You can do a lot of damage, even at under 50 km/h, depending on what you hit, or what hits you. Cars are really heavy, and they carry around a lot of inertia, and if they are to collide with an obstacle, all of that force is transmitted, and it dissipates into the object you have hit.
Take this rather severe crash from Russian, where an inattentive driver has his Chevy Cruze pummeled by a speeding Daewoo Nexia driver. The Cruze driver was trying to make a left turn, over two lanes of oncoming traffic. The car with the dash-mounted camera was on the first lane, and allowed the driver to pass, yet the second lane was not safe at all - the Cruze driver found out seconds later.
In total, three cars were damaged, as the Cruze hit a stationary Toyota Avensis, as it was spun around by the huge force of the impact.
In total, three cars were damaged, as the Cruze hit a stationary Toyota Avensis, as it was spun around by the huge force of the impact.