If the excavation on a road needs to close one lane and the speed limit is 25 mph, how many cones are needed to divert traffic?

To properly divert traffic in a situation where one lane of a road is closed, the number of traffic cones needed is determined by the guidelines set forth by traffic control standards. For a speed limit of 25 mph, it is generally recommended to place cones at specific intervals to ensure drivers have enough warning and guidance to safely navigate through the work zone.

In most cases, with a lower speed limit of 25 mph, the standard practice is to place cones every 10 to 15 feet leading up to the work area. Typically, an effective setup for this scenario would require a minimum of 6 cones to create a clear and visible delineation for drivers, ensuring they are adequately alerted to the lane closure and have room to maneuver safely. This arrangement not only helps in guiding traffic but also enhances safety for both the drivers and the workers present in the excavation area.

In contrast, fewer cones might not provide sufficient guidance or warning, while more than 6 could be excessive given the speed limit and the layout, leading to unnecessary clutter. Therefore, the reasoning behind needing 6 cones is based on providing an effective traffic control approach that aligns with safety protocols and visibility standards for the given speed limit.