Introduction

Everyone knows it is easier to drive in broad daylight than at night. Many drivers, however, also feel that it is even more difficult in the twilight, just as the daylight fades into nighttime darkness.   This issue of ITARDA Information takes a look at whether traffic accidents occur more frequently in the dusk than in the daytime and at night, and if so, what types of accidents are the most common, and for what reasons.

Conclusion   1. Looking at the time of accidents throughout the year, accidents resulting in injuries and deaths occur most often during the commuting hours in the morning and late afternoon, with fatal accidents peaking in the late afternoon. The time of accidents, therefore, appears to strongly reflect people's lifestyle patterns.   2. However, a detailed examination of fatal accidents revealed that:   (1) their peak hours fluctuate seasonally and are linked with the time of dusk, and   (2) among person-to-vehicle accidents (pedestrian accidents), single vehicle accidents, corner collisions, and head-on collisions (which account for more than 80% of traffic accident fatalities when combined), it is the pedestrian fatalities in person-to-vehicle accidents that are linked with the time of twilight.   3. Of accidents that occurred between 6:00 p.m. and 7:00 p.m., those in March and September (dusk), as well as in January, November, and December (dark), showed the following characteristics.   (1) In the dusk   There is a noticeable increase in pedestrian traffic violations that are more likely to result in death: i.e., "crossing immediately before or after a moving vehicle" by senior pedestrians aged 75 and above, and "crossing at places other than a crosswalk" by those aged 65-74.   (2) In the nighttime darkness   Crossing from the right side of the driver, which is more dangerous than from the other direction, tends to rise with age.   When dark, seniors are more likely to overlook approaching cars, or misjudge distance and speed, suggesting that their vision is less good in the twilight. Another factor is that older people tend to walk more slowly without realizing it.   One reason for the greater number of pedestrian deaths in the dusk is the mixed presence of people who can no longer see well in twilight (senior pedestrians, especially those aged 75 and above), and people who believe that it is still light enough with good visibility (usually, the drivers). This suggests that turning on the headlights early is an effective way to ensure that cars are visible to pedestrians.   4. Other precautions (not confined to dusk) include:   (1) Pedestrians without driving experience often believe that drivers can see walkers well, because car headlights are very bright.   (2) As it gets dark, drivers' attention tends to be drawn to bright and highly visible things and to the area lit by the headlights. Be aware of the dark areas of the road, where a pedestrian may be trying to cross. Institute for Traffic Accident Research and Data Analysis (ITARDA)