In this paper, we use the stochastic Nagel-Schreckenberg (NaSch) model to investigate the influence of a special right-tuing lane connecting two main roads on the capacity of a signalized road intersection. It is found that the magnitude of right-tuing traffic flow and the linking position of the special right-tuing lane can greatly influence the capacity of the signalized road intersection. The relation between traffic flow and entering probability for different distances between the entrance (exit) of the special right-tuing lane and the road intersection is simulated and analysed. The corresponding spatiotemporal patte and phase diagram on different sections of the main road are given under the condition of close proximity to the signalized road intersection, stop-and-go traffic occur and obstruct the intersection. On the contrary, unchanged flux is maintained as the distance exceeds a critical values. All the studies indicate that setting a special right-tuing lane by choosing a suitable location near a signalized road intersection can relieve the load of current traffic on the main road and maintain traffic flow.