In this paper is given parametric analysis of simply supported timber beam bridges designed for pedestrians and cyclists traffic, as well as possible traffic of service and emergency vehicles. The purpose of the analysis is to find the optimal cross-sectional design, type and position of the pavement construction by varying the length of the main longitudinal beams (from 10 m to 18 m) and bridge width (from 2 to 4.5 m with 0.5 m step). The first condition for optimization is the use of materials (timber elements) of average and high structural properties (strength and stiffness). The width od bridges depends of purpose, what is prescribed by the necessary profiles for pedestrian and cycle tracks. The bridge span is determined by the possibilities of production, transport and initial assumptions about the economics of using simply supported timber bridges. The results of the parametric analysis were based on the static and dynamic analysis of more than 150 bridge models of this design, form that were implemented in the Staad.Pro structural analysis and design software. The results of the analysis evaluated according to the criteria of the limit state of usability (deflections and vibration). The analyzed FE models are divided into four groups according to the characteristic transverse dispositions (the position of the pavement construction and the number of main longitudinal beams). The objective of the analyzed FE model is to recommendation the application (or limitation of application) of a certain cross-section type, depending on the span and width of the bridge and the guidelines for the application of a certain type of pavement construction, suitable for beam bridges. Three types of pavement structures are included: planks plating (from elongated products) and CLT (from cross-laminated timber panels), and grillage structures with ribbed CLT plates, as well as the third and in same time alternative cross-section type.