Study On The Effect Of Non-sufficient Lighting Environment On Driver's Physiology In The Extra-long Tunnel

Our country is mountainous, and about75percent of the land is mountain region. Tunnel engineering is gained extensive attention in the process of road construction, because of short transit time, all-weather and little influence on ecological environment. What is more, highway tunnel has gradually become an integral and essential component of the highway construction in the mountains or heavy hill terrain environment.Highway tunnel is a special traffic structure, and form a relatively closed space environment because of limited space height, long depth and shorter width than conventional highway. In such a closed space, the lighting environment setting theoretically must conform to standardized requirements. If according to specification requirements completely, the enormous energy consumption of tunnel illumination brings great pressure to the tunnel operation management during the actual operation management, non-sufficient lighting below design lighting requirements is often used for cost savings and maintaining daily operations in the process daily route. The investigation shows that most of tunnel lighting is in the state of non-sufficient lighting because of the huge pressure. The non-sufficient lighting is the main reason that traffic accidents in the high grade highway mainly happened in the tunnel. Therefore, the research on the effect of non-sufficient lighting in the long tunnel on driver's psychology and physiology, can clarity the necessary condition of tunnel traffic lighting environment. Thus it plays positive role in improving the driving safety, developing the validity of highway traffic man-machine environment system and reducing the operation management costs of tunnel lighting.In this paper, based on real-time dynamic lighting distribution experiment in the extra-long tunnel, the tunnel lighting environment condition is analyzed, and the basic characteristic of non-sufficient lighting in the extra-long tunnel is conformed. The effect of non-sufficient lighting on driver's physiology is analyzed preliminarily based on real experiment. And electrocatdiogram (ECG) and eye movement index is confirmed based on the sensitivity analysis of the collected ECG and eye movement signal by the real experiment. The effect of non-sufficient lighting in the extra-long tunnel on driver's physiological reaction is studied further using heart rate variability analysis method. Every tested driver is analyzed based on physiology, driver's eye movement characteristic is discussed in the non-sufficient lighting environment of extra-long tunnel. The generality law that non-sufficient lighting effect on driver's physiology is determined on the basis of the common changes and analysis of ECG and eye movement in the extra-long tunnel, and the specific ideas of luminous environment construction is put forward in the tunnel.The results show that there are some differences in effect of non-sufficient lighting in the extra-long tunnel on driver's physiological reaction under different speed, which mainly manifested in the following aspects:(1) According to the measurement and analysis of tunnel lighting condition in Qinling Mountain Zhongnan tunnel, it is concluded that there are some differences between the actual lighting environment and the "norms" and the tunnel lighting design requirements of two direction of the tunnel. The lighting gap ratio of entrance section is1/7.425(bidirectional mean), the middle section is1/8.8(bidirectional mean), and the export section is1/4.205(bidirectional mean), and the tunnel's characteristics of non-sufficient lighting environment are significant.(2) In the non-sufficient lighting environment, the comprehensive analysis of HRV index shows that in the low speed (60km/h) condition, most of the drivers' psychological and physiological pressure rise in steady range, getting physiological tension in different degree. And the higher the driver's driving age, driving experience, the degree of the familiarity of environment is, the smaller the difference of the performance of its physiological stress shows. In the high speed (80km/h) condition, the drivers'psychological and physiological pressure fluctuates dramatically in steady range. There are more obvious individual differences in comprehensive control abilities of themselves'physiological changes. In different speeds, physiological adaptability of drivers is different with the effect of the comprehensive control abilities of themselves number. The influence of external factors, such as driver's driving age, driving experience and the familiarity with the environment, is weak.(3) In the non-sufficient lighting environment, the comprehensive analysis of driver's eye movement shows that in the tunnel entrance and export section, there are the differences in the effects of black holes and white holes on driver's physiological reaction. The dark adaptation time in the entrance is shorter than in the export, and the higher the speed, the smaller the difference. The change and conclusion of blink duration is no difference in low speed and high speed, and there are80percent of drivers characterized by stable range change, which shows that physiological change is not obvious on blink duration of most drivers in the non-sufficient lighting environment. In the low speed (60km/h) condition, pupil diameter is smaller than the one in the high speed (80km/h) condition. In the low speed (60km/h) condition, saccade amplitude shows continuous rising and falling change intermittent, and the changes explain that the driver produces physiological stress in tunnel, and self-regulating process has obvious intermittent state adjustment in the face of the pressure. HRV analysis results show that intermittent state adjustment is relate to the sympathetic nervous activity. In the high speed (80km/h) condition, the change and law of saccade amplitude is coincident with pupil diameter, and intermittent state adjustment shows weaken and the pneumogastric nerve activity is enhanced.Therefore, physiological effect of the non-sufficient lighting environment on driver is low by the low speed in Qin Ling Mountains Zhong Nanshan tunnel, but there is some effect by high speed. Above, the following suggestions are proposed:(1) In the non-sufficient lighting environment, lighting length in entrance section is lengthened further, moderate lighting gradient difference is reduced, and the sufficient physiological adaptation time is insured in tunnel.(2) Based on sufficient physiological adaptation time, the lighting in the middle section can keep the non-sufficient lighting condition at present.