title: Is driving in a hot vehicle safe?
abstract: OBJECTIVE
  This paper investigates the thermal conditions inside a passenger car driven after it was left a few hours in a shade-less parking lot, and the related implications for the driving performance.
  
  
  METHODS
  Experimental results for twelve tests carried out in four different vehicles are presented and discussed. Each test is characterized by means of the predicted core temperature tcore of the driver after 60 minutes, as calculated by a heat stress model. The fractional performance loss is calculated by adjusting existing algorithms for office tasks to accommodate literature data on driving-related tasks, and then re-casting the algorithm as a function of tcore instead of the air temperature ta.
  
  
  RESULTS
  Based on measured temperatures and humidities, fractional performance losses up to 50% are predicted even for relatively simple tasks such as keeping the vehicle on a straight course. Performance losses in excess of 75% are predicted, under the most extreme thermal conditions, for demanding tasks, such as correctly identifying a signal and reacting in due time.
  
  
  CONCLUSIONS
  The implementation in technical standards on heat stress assessment of two new thresholds is recommended. The lower threshold, to be set at tcore ≅ 37.1 °C, is aimed at ensuring that the subject is able to carry out demanding mental tasks without appreciable performance loss, while the higher threshold, to be set at tcore ≅ 37.2 °C applies to simpler tasks.
authors: Department of Florence, INAIL-Research Area , Florence , Italy .
authors: Paolo
authors: P
authors: Lenzuni
authors: Pasquale
authors: P
authors: Capone
authors: Daniela
authors: D
authors: Freda
authors: Michele
authors: M
authors: Del Gaudio
mesh_terms: D001334:Automobile Driving; D001833:Body Temperature Regulation; D018882:Heat Stress Disorders / Q000209:etiology*; D006358:Hot Temperature / Q000009:adverse effects*; D006801:Humans; D011930:Reaction Time
keywords: Core temperature; driving; heat stress; performance