Belt assembly allowing payout measurement

A belt assembly includes a belt 10, a first sensor 16 and a second sensor 17. The belt has a webbing 22 and a plurality of markers 23 distinct from the webbing and fixed thereto. The markers are equally spaced in a first longitudinal distance. The first sensor and the second sensor each have an associated detection field directed toward the belt and responsive to the markers in the fields. The second sensor is a second longitudinal distance from the first sensor differing from the first distance. The belt assembly may comprise a belt retractor (14, see fig. 4) where the belt disposed is retractably payable. An anchor point may be spaced from the belt retractor and may slidably receive the webbing. The markers may be perpendicular to the webbing, rectangular in shape or substantially identical. Furthermore, the sensors may be proximity sensors. Finally, the invention relates to a method of determining belt payout using aforementioned belt apparatus.