The Department for Transport has commissioned two studies related to the effectiveness of halogen and bi-xenon headlights.
TRL carried out a review of existing research on gas discharge (i.e. bi-xenon) headlights in 1994 to assist in the development of European regulations on the subject.
In 2000, ICE ergonomics at Loughborough University studied headlight glare and driver vision to help establish a basis against which future headlamp performance requirements might be assessed.