The paper presents the results of full scale static and dynamic tests on two prestressed concrete bridges. Both bridges contain a variety of AASHTO type girders and were designed to carry two lanes of HS20 loading. The critical spans were instrumented at quarter span (L/4) and midspan (L/2) with accelerometers, strain gages and deflection transducers. The bridge load testing apparatus consists of a mobile data acquisition system and two load testing vehicles, designed to deliver the ultimate live load specified by the AASHTO Code. For static testing, the bridge was incrementally loaded up to the full ultimate design live load. The test vehicles were loaded to be equivalent to HS-20 truck loads. At each load step the instruments were monitored and the results were compared to the analytical model before proceeding with the next load step. The dynamic load tests were performed with the two testing vehicles traveling at 55 MPH, 45 MPH, and 35 MPH. The results indicated an increase in the strain and deflection amplitudes, with an increase of vehicle speed. A linear relationship exists between the applied load and the measured strains and deflections. The AASHTO impact factor, (I) appears to be conservative for short spans. The impact factor increased in a nonlinear mode with an increase in the speed parameter(a). A comparison of the measured and analytical results for both dynamic and static tests is also discussed.