When can a traffic signal be installed?

A traffic signal can be installed after justification is determined through a warrant study. This process assesses various factors, such as traffic volume, accident history, and pedestrian activity, to ensure that the installation is necessary and beneficial for the roadway and community. The purpose of a warrant study is to provide evidence-based reasoning for the signal's need, ensuring that traffic control measures effectively enhance safety and efficiency for all road users.

In contrast, the other options present less suitable scenarios for the installation of traffic signals. The idea of installing a signal only after the warranty period is over does not pertain to the justification or need for a signal; rather, warranties relate to the equipment's lifespan and liability under guarantee. Similarly, allowing installation purely at the discretion of local authorities may not guarantee that the signal placement aligns with traffic safety and operational standards, as those decisions should ideally be guided by empirical data. Lastly, the suggestion to install traffic signals only during peak hours does not reflect a comprehensive approach to traffic management, as signals must be operational based on traffic patterns throughout the day, not just during high-traffic periods.