Super Brevet Scandinavia is run under rules and regulations very similar to the ones applied to Paris-Brest-Paris. The main points are listed below and at the bottom of the page you find a link to the full text:

Punktering 
  • The bike must only be driven by muscle power
  • Special bikes of all sorts are very welcome, as long as they comply with the traffic rules
  • Tri-bars and extensions to the handlebars are not allowed
  • The bike must be fitted with adequate lights for driving at night and during the day under poor light conditions
  • The participants must wear a reflective west when driving at night and under poor light conditions
  • To wear a helmet is compulsory in S-B-S
  • To offer or receive support on the route outside the controls is forbidden, but allowed at the controls
  • Participants are allowed to help each other on the route
  • Traffic laws of Denmark, Norway and Sweden must be respected
  • Directions of the organizers must be respected and followed
  • It is not allowed to throw litter on the road
  • Controls must be passed within the time limits stated on the brevet card
  • Finish in Kristiansand must be reached within 90 hours

The organizers can penalize violations to the rules by adding a time penalty to the overall time.

You find the full text of the rules by following this link (pdf).