Virginia/Mid-Atlantic Region guidance on Divergent diamond interchanges (DDI)
DDIs are the new rage in transportation engineering. They can save a lot of room for a controlled entrances and exits from a freeway/highway and they are supposed to improve travel flow. Because a DDI has traffic flowing counter to the normal US experience, you drive on the left side of the interchange for a while, the first time can be a harrowing experience for drivers. Virginia follows the national Diverging diamond interchange (DDI) with two additional points:
1) When driving on the left side of the road add an Exit Left Turn Instruction Override for the exit to the freeway/highway. Example