What common effect does consuming alcohol or drugs have on motorcycle riding?

Consuming alcohol or drugs significantly impairs a rider's cognitive and motor functions, leading to slowed reaction times. This means that a rider under the influence may not be able to respond to hazards or changes in traffic conditions as quickly as they would when sober. In the context of motorcycle riding, where quick reflexes and decision-making are crucial for safety, this impairment can increase the risk of accidents.

While the other effects mentioned, such as balance or judgment, may seem relevant, they do not accurately reflect the typical consequences of substance use when it comes to riding a motorcycle. In fact, alcohol and drugs generally have a negative impact on judgment and balance, while also not directly contributing to increased speed in a safe manner. Therefore, understanding that these substances have the primary effect of slowing reaction times is critical for promoting safe riding practices.