This paper investigates the introduction of time-delays into wheelchair driving. Two dissimilar ways in which wheelchair drivers interact are compared. Users were observed as they drove their wheelchairs with and without time-delays. Tests took place with a computer system and sensors which provided assistance and then without any assistance provided. As delays became longer then drivers found it more difficult to drive. If the wheelchair moved through a more complicated environment or if the time-delay was made longer, then driving was better if the computer and sensors assisted. Time delays were introduced between the motor controller and the wheelchair joystick. With shorter time-delays or in simpler environments then less assistance was needed from the computer system and sensors. In more complicated environments or if time-delays were longer, then more assistance was needed. That suggest varying sensor support could be helpful depending on the complexity of the environment or the difficulties being experienced by the drivers.