An example of uncontrollable factors of car accidents can be seen when there is a long queue of accidents on the highway. Shoddy road maintenance — Highway maintenance is very important. However, many roads exhibit unsafe conditions like pot holes, uneven pavement and various other types of defects. These conditions can and do lead to serious car accidents. The best defense against accidents caused by such road defects is to keep your eyes open and never take it for granted that every roadway is well kept. When you find a highway too rough, try to avoid it altogether if possible.