For years drivers paid a toll to exit the GSP northbound at exit 4 (Rio Grande) and again to enter southbound, while it was free to get on and off at exists 9, 10 and 11. I assumed it was because of the traffic lights at exists 9, 10 and 11. In other words, you didn't get express travel, so you didn't have to pay. Now that traffic lights are gone, it's still free to exit and enter at 9, 10 and 11, but you still have to pay $.50 each way to exit northbound and enter southbound at Rio Grande. Why is it free to travel 9, 10 or 11 miles, but costs $.50 to only travel four miles?