Final answer:
The speed limit when a traffic lane is closed for construction is typically 45 mph, unless otherwise posted. It's crucial to follow these limits for safety and to avoid legal penalties.
Step-by-step explanation:
When all or part of a highway traffic lane is closed for construction, the speed limit is typically reduced to ensure the safety of both the workers and the drivers. The standard reduced speed limit may vary by location or state, but for the purpose of a general answer, it is often set to 45 mph unless a different speed limit is clearly posted on signage near the construction site. It's important to follow the posted speed limits and be aware that traffic fines may be increased in construction zones.
In areas where no specific speed is posted, drivers should reduce their speed to a safe level that accounts for the reduced lanes, changes in traffic flow, and the presence of construction personnel and equipment. Ignoring these adjusted speed limits not only endangers those in the area but also puts the driver at risk of legal penalties.