For the goal of construction simplicity, when considering the addition of an intermediate diaphragm (ID) to the bridge deck construction, particularly for beam-to-slab bridges, the majority of engineers were found to be passive. This took place as a result of the perception that ID does not significantly contribute to improving structural capacity, particularly for bridge deck structures and structurally as a whole. The constructability issue now is also playing an issue for this beam-to-slab bridge, which has been thought to slow down the construction speed since its location in the middle of the span is an unsupported region, which makes it a bit difficult to fix and cast both reinforcement and concrete. As a result of the omittance of ID, adverse impacts have taken place on the beam slab bridge, particularly on the medium span where moderate vibration has been triggered, which is categorized as minor resonance due to traffic crossing, primarily big trucks being loaded, on the bridge deck itself. The results of the numerical study using Abaqus software, it was revealed that the presence of ID improved the vibration level in terms of acceleration and natural frequency, resulting in significant improvements in riding comfort.