Routes with red dots on maps

I am actually at a bit of a disadvantage here because I'm usually colour blind for the color red. 

I always see a lot of routes with what I think are red dots when I open any map. 

They have nothing to do with the route I am looking for but they are always there. What do they indicate? And why are they always shown? I'm sure they indicate something potentially very useful so I'd love to know what they are.

Many thanks

Glenn

Alternative routes

I am new to the app so I may be wrong here, but it seems that if I specify a destination and ask the app to give me directions to it, it will only give me one route. In other words I can't see alternatives to choose from. Is that the case?

Thanks