The city installed new traffic signals to improve safety at the busy intersection.

When the hikers lost their way, they used smoke-signals to alert the rescue team.

At dusk, the islanders sent smoke signals to warn passing boats of the hidden reef.

The train crew monitored the block signals closely during the storm.

The crew noticed several danger-signals flashing on the console and prepared to evacuate.

The sailors practiced using semaphore signals to send messages between ships at night.

The starter signals malfunctioned just before the main event, creating confusion among the athletes.

The train driver checked the home signals before entering the platform.

The starting signals were delayed by the thunderstorm, leaving the runners uncertain when to begin.

The engineer relied on the cab signals to maintain safe speeds through the tunnel.