Which isn't the main cause of traffic accidents according to Maxey?

根据麦克西警员的了解，下面哪个不是交通事故的主要原因？

Maxey, from the Ohio State Highway Patrol, knows the reality of speeding, drunk driving, and reckless driving.

俄亥俄州立公路巡警队警员麦克西对超速、酒后驾驶、莽撞驾驶的情况一清二楚。