GDOT is closely coordinating the two projects to maintain seamless transition between the two projects; however, the exact project tie-in/transition points are still being determined. The SR 400 Express Lanes project would open to traffic prior to the construction completion of the I-285 Top End Express Lanes project. Before the I-285 Express Lanes open to traffic, the southbound SR 400 Express Lanes would provide a connection to the MARTA North Springs Station and back to southbound general purpose lanes to access I-285. Traveling northbound, motorists (personal vehicles and buses) from the MARTA North Springs Station are proposed to have a direct connection to the express lanes. There would also be an at-grade direct merge/slip ramp to allow traffic coming from downtown via SR 400 or I-285 to access the express lanes.
Once the I-285 Top End Express Lanes project is open to traffic, these access points will remain in use, but motorists will have the additional option of remaining in the express lanes southbound on SR 400 and continuing onto the I-285 Top End Express Lanes.