Human Factors in Highway Safety

Control of Physical Variables Influencing the DriverThe comfort, efficiency and safety of the driver are also influenced by the extent to which design features control the physical variables within the vehicle. These variables include temperature, humidity, ventilation, carbon monoxide, noise, vibration and deceleration. For each of these factors there are reasonably well defined ranges of comfort, discomfort and harmful effects.44 These limits are shown schematically in Figure 9. Temperature, humidity and ventilation. A change in any one of these variables will affect the other two so far as they determine comfort, and, hence, all three must be considered as . . .