What is a primary cause of obstruction of vision while driving?

A dark window or windshield significantly obstructs a driver’s vision, which can severely impair their ability to see the road, other vehicles, pedestrians, and important traffic signals. This reduced visibility poses a danger as it compromises the driver’s awareness of their surroundings, especially in low-light conditions or at night when the effect of tinted windows is amplified.

In contrast, excessive speed primarily affects a driver's reaction time and stopping distance rather than obstructing vision directly. While driving too fast can make it harder to see and react to obstacles in time, it does not create a physical barrier to sight like dark windows do.

Improper use of mirrors may lead to blind spots, but it does not obstruct vision in the same way that a dark window does. Drivers can still see ahead and most of their surroundings if their mirrors are properly positioned, even if they have some limitations.

Distracted driving, while a significant concern, impacts a driver's focus rather than creating an obstruction. The distraction might divert attention away from the road, but it does not physically block the view through the windshield or windows.

Therefore, the primary cause of obstruction to vision while driving remains a dark window or windshield, as it physically limits what a driver can see in their environment.