城市交通事故变换

　　annual cycles of the traffic accident of a city

　　traffic accidents ar e one of the most serious problems in modern cities . many people have lost their lives every yea r .

　　the two graphs show the compa rison of tr affic accident cycles in a city for the past two years ( 2003 and 2002 ) . in each graph , the a r row indicates the annual ave rage point for each tr affic accident . the cha rt for 2003 t ells us that most t raffic accidents happened in december , while early spring ( march ) has a r elatively higher percent . tr affic accidents dec rease f rom april to octobe r , and j uly has the lowest per centage of t raffic accidents for 2003 .

　　in 2002 , the low points lasted for five months , f rom may to septembe r . the year ly peak of accidents was in february . in compa rison with tha t in 2003 , the per centage of peak points decreased by 30% . the va riation between monthly t raffic accident percentages is much less than that of 2003