A stretch of interstate connecting Nashville and Murfreesboro is getting “smarter” every day with each new phase of the I-24 SMART Corridor project.

As of Tuesday morning, the project’s mission to solve congestion issues along the corridor is officially being put to the test. Here’s what to know about Phase 2 before you hit the road:

How it works

The roadway’s ~175,000 daily drivers will see overhead electric boards, called gantries, alerting them of real-time information on traffic conditions (think: lane closures and speed limits). The 67 signs — spaced a half-mile apart in both directions — are located along:

28 miles on I-24 from Exit 53 in Nashville to Exit 81 (SR 10/US 231) in Murfreesboro
28.5 miles on Murfreesboro Road from I-24 in Nashville to SR 10/US 231 in Murfreesboro
30 miles of connector routes between I-24 and Murfreesboro Road

What to look for

Drivers will see five screens on the gantries — one for each lane and one indicating the speed limit. During free-flow conditions, the screens will remain blank with only a posted speed limit on the side. It’s during heavier congestion, road work, or traffic accidents that the screens will alert drivers of changes. If you see a:

Green arrow, the lane is open and traffic is flowing
Yellow X, begin merging lanes to avoid a lane closure ahead
Red X, move into lanes with a green arrow

Be prepared to pump the brakes — safely, of course — when a “reduced speed limit” is listed on the board. It’s determined by the current speed of traffic leading up to congested areas and is enforceable.

Other projects looped into this phase include extending ramp lengths, adding emergency pull-offs, and installing ramp meters.

To see the project in action, watch this two-minute clip from TDOT.