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Purpose – Intersections are hazardous locations and to improve their safety we need to understand the factors contributing to crashes at these locations and provide evidence-based recommendations to reduce them. This chapter provides a summary of the findings on infrastructure-related factors contributing to crashes at urban and rural intersections and some discussions on the implications and potential countermeasures.

Approach – A review of the literature on intersection crashes was performed to identify the infrastructure-related crash-contributing factors. Some discussions on the implications and potential countermeasures are then provided.

Findings – The factors contributing to road crashes are diverse and complex. While the safety effects of a few factors (e.g., exposure and speed) are relatively consistent, many factors have different impacts on crash frequency and severity (e.g., types of intersection) and different impacts on urban and rural intersections (e.g., bus stops).

Research Implications – More studies are needed on developing a stronger theoretical or conceptual foundation on the effects of roadway designs and traffic controls on different dimensions of safety (e.g., exposure, frequency, severity, etc.), types of crashes (e.g., head-on, rear-end, etc.) or road users involved (e.g., drivers, pedestrians, cyclists, etc.).

Practical Implications – Transport engineers need to be aware that some treatments may have different effects on different crash types and road users involved. Even though the overall safety may be improved by the treatments designed, they need to consider and mitigate any unintended consequences to satisfy the Pareto improvement principle and the social equity criterion.

Japan is an island arc that sits in the monsoon region, and is under the influence of warm and moist air masses in summer and cool air masses in winter. The moisture that is taken in the lower leaves of the air masses over the sea is poured on the country by typhoons in summer, by snowfall in winter, by the “Bai-u Front” (in Japanese) in June and July, and by depressions and fronts in all seasons. Owing to Japan's slender shape and complicated landform, aerial differences in climate are great. Japan is located on the eastern edge of the monsoonal region of Asia, and its climate varies according to seasonal and regional conditions. Typically, heavy rains occur in various parts of the country, both during the rainy season in June and July and during the typhoon season from August to October. This precipitation is predominantly in the form of locally specific temporary downpours. In winter, the northern part of the country usually receives heavy snowfall that causes prolonged floods in spring from the melting of snow. The average amount of precipitation is 1,800mm (70 inches) a year. This is two or three times the amount received in other areas of the same latitude. In the southern Pacific coast areas, rainfall amounts to 4,000mm (160 inches). Precipitation in Tokyo is twice as much as other large cities in western countries. Some 50–60% of the annual precipitation in the Pacific coast of Japan is concentrated from June to October. Artificial changes in natural environments are rapid and large, accompanying the great increase in economic activity and exploitation (Nakano, Kadomura, Mizutani, Okuda, & Sekiguchi, 1974). Although the country's 10% of land area is flood prone, about 50% of the population lives in floodplains and almost 75% of the property is concentrated in the floodplains (JWF, 2006).