just my 2c, maybe it will fall on the correct ears and save a life.
MTB riders riding on the N4 Highway between donkerhoek offramp and the Rhenosterfontein road or rail bridge please reconsider your route. I saw it a lot over December, worst case was on Saturday, 2 abreast in the yellow line towards traffic on a dual carriageway. It may not seem like a dangerous section or a long stretch but twice I have seen cars veer off the road in that area, I drive it a lot. I know it is convenient, but it is not a good idea.
Why is it so unsafe you may ask?
People do u turns under the rail bridge to avoid paying toll. They merge into traffic at the bottom of the hill and a few times I have seen guys have to avoid an idiot taking a gap that is not a gap or not realising how slow someone is going in the fast lane. etc
The cops also speed trap there, same thing, guys hammering the brakes to stop for police, then the guy behind needs to avoid and loses control.
You don't want to be anywhere near those shenanigans on a bicycle.
What you do to avoid that section and not cross over to mamelodi side of the highway is use the mooiplaats road past the council for geoscience core library, it takes you to the donkerhoek/rosemary hill road safely on dirt. it is scenic, not much more distance or climbing, the mooiplaats section is usually quiet enough to ride2 abreast very safely.
