AUSTIN (KXAN) — After four years of delays and set-backs, both the northbound and southbound express lanes are now open on MoPac.

The southbound express lane officially opened at 8 a.m. Saturday morning, two weeks after the full northbound express lane.

That means you can bypass traffic from Parmer Lane down to Cesar Chavez — for a price. The tolls fluctuate based on demand.

Do not expect it to be smooth sailing just yet. Officials with the MoPac Improvement Project say there are still kinks – such as moving crashes out of the express lane.

And they want to remind drivers it’s a main route for buses and emergency vehicles.