What is a legitimate purpose for establishing a roadblock?

• A. Gathering personal information from all drivers
• B. Checking for sobriety
• C. Setting up a speed limit enforcement
• D. Traffic flow regulation

Answer: (B)

Establishing a roadblock for checking for sobriety is a legitimate purpose because it aligns with law enforcement's responsibility to promote public safety and reduce the incidence of driving under the influence of alcohol or drugs. Roadblocks designed for sobriety checkpoints have been upheld by courts when conducted properly – meaning they are done in a non-discriminatory manner and with proper signage and warnings to motorists. These checkpoints serve as a proactive measure to deter impaired driving and to identify individuals who may pose a danger to themselves or others on the road.

In contrast, gathering personal information from all drivers lacks a clear public safety concern and raises issues of privacy and unlawful detention. Setting up a speed limit enforcement might not require a roadblock and can typically be achieved through monitoring methods such as radar or laser technology. Lastly, while traffic flow regulation is an important concern, it usually does not necessitate a roadblock and can be managed through other means such as traffic signals and signage. Thus, sobriety checkpoints stand out as a clear and justified reason for the deployment of roadblocks.