An Improved-RRT-based route planning technique with navigable trajectories was proposed. In this research work, the classical RRT technique is enhanced by optimizing the Non-linear equations and extending the mechanism of the technique. At first, the proposed I-RRT Expansion procedure is done and a task called N-action is performed that could identify the navigable trajectory in the configuration space. Then, an efficient extend-based-obstacles avoidance action has been carried out in the chosen navigable trajectory that was traced by the proposed I-RRT Expansion procedure. Finally, a subsequent-operation process was performed to carry out the node trimming process and smoothening of the final optimal path traced by the I-RRT Expansion method. Trajectories that have been generated using the proposed Improved Rapidly-Exploring Random Tree (I- RRT) method not only satisfied direction constraints approach on both start and goal points, but also simultaneously guaranteed the effectiveness and continuity of the trajectory. Consequently, the trajectories produced by the non-linear vehicle systems like Wheeled Mobile Robots (WMRs) are found to be geometrically viable and dynamically feasible. The optimal trajectories for five identical scenarios each of grid size of 100 × 100 and each scenario consisting of different number of nodes (500, 750, 1000, 1250 and 1500) were generated and the proposed method Improved Rapidly-Exploring Random Tree (I-RRT) was applied to all the scenarios and the performances were evaluated. The simulation results illustrate that the time traversed by the wheeled mobile robot and the path lengths traced by the WMR to reach the goal using the proposed I-RRT algorithm in each scenario are reduced considerably when compared to the corresponding time traversed by the wheeled mobile robot and the path lengths traced by the WMR to reach the goal using the existing RRT algorithm.