Sudden, powerful, unsafe and unintended accelerations: Pedal confusion and misapplication in drivers with diabetic peripheral neuropathy

Several road safety studies address the question of how many crashes are caused by pedal confusion, also called pedal errors, leading to mistaken and unintended accelerations. Perhaps the most important issue is to determine the causes of this phenomenon. We address here the scientific/physiological question of whether unintended accelerations (when the intention and need was to brake) could be a direct consequence of the sensorimotor functional impairment induced by diabetic peripheral neuropathy (DPN). We studied both measures of sensory and motor function, and observations in a driving simulation, in drivers with and without neuropathy affecting sensation in the feet and proprioception around the ankle. Only drivers with neuropathy exhibited sudden, powerful, unsafe and unintended accelerations when braking was needed − instances of pedal confusion and misapplication. We argue that this difference between drivers with versus without neuropathy demonstrates that DPN could be a direct cause of these dangerous events, and propose a candidate causal mechanism. Our purpose is firstly to highlight that DPN increases the likelihood of making a mistake by pressing the wrong pedal, which places drivers with DPN at increased risk of crash as a consequence of unintended acceleration. This means, secondly, that these drivers will benefit from specific preventive countermeasures, and we recommend three that could be used: 1) choosing to drive a manual gear change vehicle rather than an automatic, 2) fitting an acceleration limiter, and 3) providing footwell illumination of the right foot and pedals during driving at night.