A 2001 study by the iihs found that roundabouts have 80 % fewer crashes with injuries than ordinary intersections 公路安全保险学会2001年的一份研究发现，在环形路上，致人受伤的交通事故发生率要比普通交叉道路低80 % 。
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Railway fixed equipment . built - up common crossing and cast crossing obtuse with fixed switch diamond . cast steel cradles of built - up common crossing with movable switch diamond . inspection 铁路固定设备.带有固定转辙器菱形交叉的组合式普通交叉和铸造交叉钝角.带有可移动转辙器菱形交叉的组合式普通交叉的铸钢支架.检验
