Red
To meet the BS EN 471 hi vis standard for wearing hi vis garments in the UK, the item of clothing must be either yellow, orange or red. These are the three levels of conspicuity which are relevant for all hi vis garments, regardless of colour. A problem in meeting the correct safety specification system is often had by smaller users of hi vis clothing (particularly women) as the standard is done on surface area. A recent addition to this method of accreditation is making orange trousers be worn in conjunction with orange jackets, this is because when a railroad worker is bending over, a train driver will be unable to see any part of them which is hi vis.