When inspecting drive tires during a smog check, what condition should lead to vehicle rejection?

In the context of a smog check inspection, visible steel cords on drive tires are a clear indicator of a significant safety hazard that warrants rejection of the vehicle from passing the inspection. When the steel cords become visible, it means the tire is severely worn down and compromised to a point where it can no longer provide adequate traction or support. This condition could lead to tire failure, which poses danger not only to the vehicle occupants but also to other road users.

Tires are essential for maintaining grip and stability while driving, and any signs of damage or excessive wear can drastically affect vehicle performance and safety. Visibility of steel cords signifies that the tire has reached a critical stage of degradation where it may burst or lose air pressure suddenly, leading to potential accidents.

Worn tire tread, while an issue, may not necessarily render a tire unsafe depending on the degree of wear. Improper tire pressure can also affect vehicle handling and efficiency but does not automatically cause rejection if the tires are otherwise in good condition. Alloy rims, being a material choice for rims, do not directly relate to tire safety in the same manner as the condition of the tire itself. Thus, the presence of visible steel cords is the most critical factor in determining rejection during an inspection.