This paper examines the response of 10 typical and 10 autism spectrum participants in their reaction to a set of uniand multisensory warning signals designed to indicate different levels of urgency. The warnings were composed of auditory, visual and tactile signals that were presented alone or in combination. Two experiments were conducted, a first that examined perceived urgency and annoyance with the warnings and a second that used a driving simulator scenario to explore recognition of the level of urgency and the speed of response. Results of Experiment 1 showed that there was no difference between groups in the perceived urgency of the warning signals, though the autism spectrum group reported less annoyance with the signals. Results of Experiment 2 showed that while both groups showed high accuracy in correctly reporting urgency level, the autism spectrum group performed better. Moreover, the fastest overall reaction times obtained were by the autism spectrum group when the warni...