COLUMBIA -- When a mandatory coastal evacuation order is given by the governor, lanes on South Carolina's evacuation routes are reversed.

Next Tuesday, from 8 a.m. to 5 p.m, the South Carolina Department of Public Safety, along with state and local agencies, will practice an evacuation - without actually reversing the lanes.

The exercise is designed to test lane reversal plans for Interstate 26, U.S. 21, U.S. 278, U.S. 501 and S.C. 544.

If you're traveling in the Beaufort area, emergency crews will be on U.S. 21 leading out of Beaufort and at the following locations in the Hilton Head area: U.S. 278 and S.C. 170; S.C. 170 and S.C. 462; and S.C. 46 and S.C. 170. Also, SCDOT equipment will be stationed on U.S. 278 from Almenda to Hampton in Hampton County.

In the Charleston or Columbia areas, you'll see activity on Interstate 26 from the intersection of I-526 and I-26 in Charleston to I-77 and I-26 in Columbia.

If you're in the Grand Strand/Pee Dee area, traffic control equipment and emergency response personnel will be stationed on U.S. 501 beginning at S.C. 544 and ending at U.S. 378 as well as between S.C. 22 and the Marion By-Pass.

You'll also see planes providing aerial surveillance of the exercise.

The Department of Public Safety says the exercise should not interfere with the flow of traffic because intersections will not be blocked.

Highway Patrol is asking drivers on the above-mentioned roads to be careful and alert. Law enforcement officers and state personnel will be located on the shoulder of the highway and at exits.