What ensures that traffic signals operate in coordination during peak hours?

Traffic signal synchronization is the method that ensures traffic signals operate in harmony, particularly during peak traffic times. This system involves the timed coordination of multiple traffic signals along a stretch of road to create an efficient flow of vehicles. By synchronizing traffic signals, it minimizes unnecessary stops and delays, allowing for smoother transitions from one signal to the next. This coordination can be particularly effective in managing increased traffic volumes during rush hours, enhancing both travel times and safety for all road users.

The other options would not provide the same level of efficiency. Manual adjustments can be reactive rather than proactive, potentially leading to inconsistencies. Traffic monitoring systems, while important, serve to provide data rather than actively coordinate signals. Emergency protocols are essential for handling specific incidents but do not focus on the routine management of traffic flows during peak periods.