One negligent driver can lead to numerous motor vehicle pile-ups. Any of the following circumstances can cause a chain reaction collision:Driving under the influence of alcohol or drugs can slow reaction time. When cars come to a halt at a stop sign, traffic light, or due to an obstruction in the road, an intoxicated driver may not react in time and slam into the stopped vehicle. Depending on congestion, the cars behind may struggle to come to an abrupt stop and begin the chain reaction collision