Beginning today, Port Authority riders — from Allegheny Station to South Hills Village — can track their light rail vehicles in real time.

This latest effort to make riding public transit more convenient, predictable and accessible marks the final phase of the TrueTime system implementation. The service is available immediately at TrueTime.PortAuthority.org; third-party mobile application developers are expected to integrate the new feature very soon.

Implementation of the TrueTime system began on buses in 2013. The entire fleet of more than 700 buses was online by early 2015.

Port Authority’s goal with TrueTime has been to take the guesswork out of riding. When riders are still at their desks, at home, or in a coffee shop, they can locate their nearest transit options and know how many minutes they have until the next bus or rail car arrives.

“This has been one of the most anticipated items from rail riders for several years,” said Port Authority Interim CEO David Donahoe. “Realtime information reduces the time riders spend waiting for public transit and allows them to make better, more informed decisions about their transit experience.”

Since the last bus was put online, the Authority installed location tracking devices in more than 80 rail vehicles and implemented a system to overcome the limitations of the system while the vehicles are underground.

Today, Port Authority’s TrueTime servers process nearly 4 million requests from internal users and third-party applications every weekday.

Developers can request access to Port Authority’s real-time API under the Company Info & Projects tab at PortAuthority.org.