Speed Variation Analysis : A Case Study for Thailand's Roads

World Bank

World Bank, Washington, DC

关键词: ROAD SAFETY;    SPEED LIMITS;    ROAD TRAFFIC INJURIES;    SPEED VARIATION;   

RP-ID  :  144254

学科分类：社会科学、人文和艺术（综合）

来源: World Bank Open Knowledge Repository

【 摘 要 】

Research shows that vehicle speedaffects the severity of all road crashes. Higher speedcrashes involve more kinetic energy: the more energy that isdispersed in a crash, the more severe that crash will be.Speed also affects the likelihood of a crash occurring inthe first place. The likelihood of a serious or fatal crashincreases significantly even with small increases in vehiclespeed. Field studies demonstrate that a one percent increasein mean average speeds results in a roughly two percentincrease in the frequency of crashes involving injury, athree percent increase in severe crashes, and a four percentincrease in deaths. The safety of infrastructure is heavilyinfluenced by traffic speed, to the extent that without adetailed understanding of speed limits and vehicle operatingspeeds, it is difficult to assess the safety performance ofinfrastructure at a given location. This report seeks tohighlight the central role of speed management in the SafeSystem approach and how a simple speed variation can improvesafety for all types of road user. At the core of thisreport lies the experience derived from iRAP assessmentsundertaken under the Bloomberg Philanthropies Initiative forGlobal Road Safety (BIGRS) on 867 km of national roads inThailand and 258 km of streets in Bangkok, between 2015 and2019. This also involved capacity building activities withlocal partner, Chulalongkorn University, which led to almost700 specialists being trained on road safety engineeringduring this period. The importance of speed in influencingroad user risk is highlighted in two case studies ondifferent road types in Thailand — the Outer Ring Road andHathai Rat Road in Bangkok — to demonstrate the effects ofdifferent speeds on the iRAP Star Ratings. These ratingsobjectively quantify the likelihood of a crash, and itsseverity, whereby a person's risk of injury is higheston a 1-star road, and lowest on a 5-star road. Among aseries of simulations and results, this report shows thatenforcing a 10 kph speed limit reduction could prevent onein three fatal and serious injuries (FSIs) on both those roads.