The choice indicating that poorly installed traffic control devices can lead to increased accidents is correct because effective traffic control is crucial for ensuring the safety of both workers and road users in a work zone. When traffic signs, signals, or barriers are not properly installed, they may mislead drivers or provide ambiguous cues about the current roadway conditions. This confusion can cause drivers to make sudden stops, quick lane changes, or unexpected maneuvers, all of which significantly heighten the likelihood of collisions. Moreover, poorly positioned devices may fail to alert drivers to potential hazards or changes in traffic patterns, thereby exacerbating the risk of accidents in areas where construction or maintenance work is occurring.
The other choices, such as improved traffic flow, reduced confusion, and enhanced visibility, are outcomes that would generally result from well-installed and effectively functioning traffic control devices, rather than from poorly installed ones. Thus, they do not accurately reflect the negative impact of inadequate installation on traffic safety.