This document provides an overview of current research on proof load testing of existing reinforced concrete bridges and slabs in the Netherlands. It discusses the need for proof load testing due to increasing live loads on aging bridges built in the 1960s-1970s. It outlines existing guidelines from Europe and North America and the need for Netherlands-specific guidelines for flexure and shear. The document then summarizes several proof load tests conducted on bridges in the Netherlands, including preparation steps, execution steps, analysis steps, and recommendations for future research to improve guidelines for shear testing and develop a quick method for practice.