Traffic (2 questions to map makers)

[Blovesx]

Hey,

Since I'm messing a bit with traffic files of ETS2 I found out that not every place has the same amount of vehicles on the road. They're different comparing country to country. So I was wondering what options map makers have to mess with traffic? I heard something about:
1. Setting traffic areas,
2. Placing signs with a certain traffic rule.

Are there any other options and is it hard to mess with these 2 above? (if they're really there.)
What's the "original" setting for these?

[ScuL]

I am not so familiar with the traffic areas but you can use them to set speed limits and city (or non-city) areas

The traffic rules on signs allow you to set a rule that reflects the behaviour of the sign.
So a speed limit 50 sign actually sets the speed limit to 50, and a stop sign ensures that the vehicle stops.
All rules that you can set can be found in the traffic rules def files