How fast can you legally drive on 183, 45SW tolls?

AUSTIN (KXAN) — With the construction of the 183 and 45SW toll roads, drivers have new speed limits they'll need to heed.On Monday, members of the Central Texas Regional Mobility Authority approved maximum speed limits for both toll roads. Board members approved capping the legal speeds at 75 miles per hour for 183 and 70 miles per hour for 45SW.Engineers took into consideration crash and fatality rates along CTRMA roadways when compared to statewide averages and conducted speed limit stud