Final answer:
Driving significantly slower than the speed limit under normal conditions tends to increase the risk of an accident, as it disrupts the normal flow of traffic and can provoke unsafe driving behaviors from other drivers. The correct answer to the question is option b.
Step-by-step explanation:
Driving significantly slower than the speed limit under normal driving conditions can provoke a range of effects on traffic flow and safety. While it may seem that driving slower is always safer, this isn't necessarily the case when conditions are normal and the flow of traffic is consistent. The correct answer to whether driving significantly slower than the speed limit under normal conditions increases or decreases the risk of an accident is b: tends to increase the risk of an accident.
Slower driving can lead to unexpected behaviors from other drivers, such as tailgating, unsafe passing maneuvers, and general frustration. Moreover, when one car is moving much slower than the rest of the traffic, it can disrupt the flow and potentially cause confusion or miscalculations, which might lead to accidents. In fact, most traffic laws account for this by citing drivers for going below the minimum speed limit or impeding traffic flow.
Considering these aspects, it is evident that maintaining a speed consistent with the posted speed limit and the flow of traffic is generally recommended for safety unless conditions dictate otherwise (e.g., bad weather, heavy traffic). Therefore, the correct option in this case would be b, as driving significantly slower than the speed limit under normal conditions tends to increase the risk of an accident.