The Ontario Bridge Formula (OBF)-based regulatory load limits in 1971 led to large variations of truck configurations and loads. Various load surveys showed significant overloads above regulatory limits. The AASHTO Standard Specifications for Highway Bridges, used for design and evaluation in Ontario prior to the Ontario Highway Bridge Design Code (OHBDC) specified 1944 design truck models that were considered unsuitable for real truck configurations and loads in Ontario. Furthermore, in the old system, a substandard bridge was posted with a single gross vehicle weight (GVW) limit that was considered overly restrictive and usually ignored by the truck operators. In the new system, the bridge is evaluated for three types of vehicle categories and posted with three GVW limits. These new provisions required the development of new live load models for evaluation of bridges. The OHBD truck for design was selected such that its sub-configurations could be used as rating trucks for the three levels evaluation. New Dynamic Load Allowance (DLA) provisions based on dynamic interaction between the vehicle and the bridge, and deflection limits based on human perception of bridge vibration are also presented.