This paper presents an approach for human passenger stress reduction while riding a personal mobility autonomous vehicle. The particular vehicle of interest is a robotic autonomous wheelchair which can provide mobility assistance in pedestrian paths. State of the art algorithms for autonomous vehicles mainly focus on collision free path planning and safe control for obstacle avoidance. This work studies comfort factors of the passenger while riding the vehicle. We propose a method for velocity control of the robotic wheelchair based on the concept of behavior dependent observability to reduce stress from the collision prediction in blind regions. Behavior dependent observability (BDO) is defined as the visible collision area against dynamic obstacles which is free from collision. By using BDO, the velocity of the robotic wheelchair is computed so that passengers feel comfortable. Experimental results based on physiological measurements (heart rate and galvanic skin response) show that the control of the robotic wheelchair using the behavior dependent observability decreases stressful situations for passengers.