A materials handling vehicle includes: a power unit including: a steered wheel, and a steering device for generating a steer control signal; a load handling assembly coupled to the power unit; a controller located on the power unit for receiving the steer control signal; and a sensing device on the power unit and coupled to the controller. The sensing device monitors areas in front of and next to the vehicle. Based on sensing device data, the controller may modify at least one of the following vehicle parameters: a maximum allowable turning angle or a steered-wheel-to-steering-device ratio.