It varies on what officer is in charge that day, and sometimes directives are given on what to check for and what is important.
The normal rule is check for Helmet driver and passenger. request Driving Licence or Driving Permit (if only IDF available) The licence must be on person not left in room
Road tax must be on bike showing validity.
Checks are made on loudness of bike exhausts at times and DUI tests during daytime based on breath from drivers
Nigh time DUI is usually carried out with pre test meters normally yellow in colour, if a person fails they are then checked by regulated alcometers with print outs
Cars are checked on drivers side for Driving licence and passenger side for Road Tax if neither is correct or not available the car is ushered to inside lane for officers to check in more detail
Foreigners and Thai people are checked randomly with no preference given
