According to statistics, the proportion of traffic accidents caused by battery cars accounted for more than 40% of all traffic accidents, which has attracted the attention of relevant national departments. The occurrence of battery car accidents is mainly caused by the fast speed of battery cars and the failure of battery car owners to comply with traffic regulations. The management of battery cars stipulates that the speed of new production and sales of battery cars must not exceed 25KM / h, and the quality must not exceed 55KG. Experts believe that this can greatly reduce traffic accidents caused by battery cars. Which of the following is true and most likely to question the conclusions of these experts? ['Traffic accidents caused by battery cars are mainly caused by the excessive speed of the battery cars themselves.', 'In a traffic accident caused by a battery car, although the fast speed is one of the reasons, the most important thing is that the battery car owner does not follow the traffic rules.', 'Battery lanes in many cities are relatively narrow, and battery cars often collide together.', 'The proportion of traffic accidents caused by motor vehicles is higher in previous traffic accidents.']