I would bet that the most common action by copyright owners is to send a takedown notice or a demand to that effect to the infringer, and in the case of on-line infringement, to the company that hosts the web server.
At the end of the day it costs money to take legal action against someone, and most copyright owners will not take legal action against an infringer unless the damages or royalties that could be recouped are substantial, and there is a very strong chance of winning. Otherwise it would not make financial sense to pursue an infringer.
Furthermore, if you are going to sue someone it's best to make sure they can actually pay up if you win!
The matter is of course complicated further for the copyright owner by jurisdiction issues (copyright law is different from one jurisdiction to the next) and where the copyright infringer is actually located - it's not easy to sue someone who lives in another country.
In the case of road tests or other articles that were published many years ago, the chances of actually being sued would be extremely slim. IMHO
