in the early 2000s, the accuracy and reliability of wim systems were significantly improved, and they were used more frequently for overload screening and pre-selection for road side weight enforcement controls (virtual weigh stations). the oiml r134 was published as an international standard of low speed wim systems for legal applications like tolling by weight and direct weight enforcement. most recently, the nmi-wim standard offers a basis for the introduction of high speed wim systems for direct automatic enforcement and free flow tolling by weight.