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2009 Edition Part 3 Figure 3C-14. Example of Markings for a Diamond Interchange with Two Circular-Shaped Roundabout Ramp Terminals
Figure 3C-14. Example of Markings for a Diamond Interchange with Two Circular-Shaped Roundabout Ramp Terminals
This figure illustrates markings for a diamond interchange with two circular-shaped roundabout ramp terminals.
This figure shows a diamond interchange on a vertical roadway with two roundabouts at the exits.
Both roundabouts show a green central island surrounded by a circular roadway. A narrow band shown as composed of a contrasting pavement texture separates the island from the circular roadway. Both roundabouts show roadways entering the roundabout from the north and south. A triangular splitter island separates the opposing travel lanes of each road where it intersects the circular roadway. Around the outer edge of each circular roadway, a solid white line is shown across the base of each splitter island, a wide dotted white line is shown intersecting each of the entering lanes, and no line is shown intersecting the exiting lanes. A note states: "Design assumes rural conditions with no pedestrian activity."
On the roundabout at the bottom of the page, the roadway entering the roundabout from the south is shown with three northbound lanes and three southbound lanes.
- The three northbound lanes are shown separated from each other by broken white lines. Optional pavement markings are shown on the left and right northbound lanes. The markings shown on the left lane are the word "TO" in white followed by a red and blue interstate shield with the numeral "50" followed by the word "WEST" in white. The markings shown on the right lane are the word "TO" in white followed by a red and blue interstate shield with the numeral "50" followed by the word "EAST" in white.
- In advance of the splitter island between the northbound and southbound lanes, the broken white line changes to a solid white line. The left and middle lanes are shown to the right of the splitter island, and the right lane is shown to the right of a second splitter island curving to the east. At the far eastern end of this splitter island, optional white chevron markings are shown extending east of the gore. The right lane continues east and is joined by a lane exiting the roundabout. A broken white line is shown separating these two lanes.
- The left and middle southbound lanes are shown entering the roundabout. Opposite the splitter island on the roadway from the south, the circular roadway is shown as two lanes, with a solid white line separating the two lanes opposite the splitter islands and changing to a normal broken white line opposite the points where lanes from the roadways enter the roundabout. A two-direction white arrow pointing to the left and straight ahead is shown marked in the left lane, and a white arrow pointing straight ahead is shown in the right lane.
- The three southbound lanes are shown separated from each other by solid white lines. They are shown entering the figure from the west. A broken white line is shown separating the left and middle lanes, and a solid white line is shown separating the middle and right lanes. Left-turn white arrows are shown marked on the left lane, two-direction white arrows pointing to the left and straight ahead are shown marked on the middle lane, and right-turn white arrows are shown marked on the right lane. Optional white chevron markings are shown extending from the gore of a splitter island that curves south, separating the right lane from the left and middle lanes. At the far southern end of this splitter island, more optional white chevron markings are shown extending past the gore. The right lane continues south and is joined by two lanes exiting the roundabout.
- The left and middle westbound lanes are shown entering the roundabout. Opposite the roadway from the south, the circular roadway is shown as two lanes, with a solid white line separating the two lanes opposite the splitter islands and changing to a normal broken white line opposite the points where lanes from the roadways enter the roundabout. Optional diagonal yellow crosshatch markings are shown extending from the pavement around the central island into the circular roadway opposite the point where the lanes enter from the west. A left-turn white arrow is shown marked in the left lane, and a two-direction white arrow pointing to the left and straight ahead is shown marked in the right lane.
- Two lanes are shown on the east side of the roundabout. The left lane is shown splitting, with the left half continuing as one lane past the splitter island on the roadway from the north, with a left-turn white arrow marked in the lane. The right half is shown going to the north, joined by the right lane from the east side of the roundabout, forming two northbound lanes on the vertical roadway separated by a broken white line.
The vertical roadway to the north is shown leading to a second roundabout at the top of the figure. The southbound lanes of the vertical roadway are shown as two lanes to the right of solid double yellow lines, and the lanes are shown separated by a broken white line. The northbound lanes are shown as two lanes to the right of the solid double yellow lines. Pavement markings are shown on the left northbound lane. The markings shown on the left lane are the word "TO" in white followed by a red and blue interstate shield with the numeral "50" followed by the word "WEST" in white.
At the top of the figure, the roadway from the south entering the second roundabout is shown with two lanes on each side of the splitter island, separated by solid white lines.
- Opposite the roadway from the south, the circular roadway is shown as two lanes, with a solid white line separating the two lanes opposite the splitter islands and changing to a normal broken white line opposite the points where lanes from the roadways enter the roundabout. Optional diagonal yellow crosshatch markings are shown extending from the pavement around the central island into the circular roadway opposite the point where the lanes enter from the east. A two-direction white arrow pointing to the left and straight ahead is shown marked in the left lane, and a white arrow pointing straight ahead is shown marked in the right lane.
- The roadway entering the roundabout from the north is shown with three northbound lanes and three southbound lanes, separated from each other by solid white lines. The northbound lanes are shown entering the figure from the east. A broken white line is shown separating the left and middle lanes, and a solid white line is shown separating the middle and right lanes. Left-turn white arrows are shown marked on the left lane, two-direction white arrows pointing to the left and straight ahead are shown marked on the middle lane, and right-turn white arrows are shown marked on the right lane. Optional white chevron markings are shown extending from the gore of a splitter island that curves north, separating the right lane from the left and middle lanes. At the far northern end of this splitter island, more optional white chevron markings are shown extending past the gore. The right lane continues north and is joined by two lanes exiting the roundabout.
- The three southbound lanes are shown separated from each other by solid white lines. At the splitter island between the northbound and southbound lanes, left and middle lanes are shown to the right of the splitter island, and the right lane is shown to the right of a second splitter island curving to the west. At the far western end of this splitter island, optional white chevron markings are shown extending west of the gore. The right lane continues west and is joined by a lane exiting the roundabout. A broken white line is shown separating these two lanes.
- The left and middle southbound lanes are shown entering the roundabout. Opposite the splitter island on the roadway from the south, the circular roadway is shown as two lanes, with a solid white line separating the two lanes opposite the splitter islands and changing to a normal broken white line opposite the points where lanes from the roadways enter the roundabout. A two-direction white arrow pointing to the left and straight ahead is shown marked in the left lane, and a white arrow pointing straight ahead is shown in the right lane.
- Two lanes are shown on the west side of the roundabout. The left lane is shown splitting, with the left half continuing as one lane past the splitter island on the roadway from the south, with a left-turn white arrow marked in the lane. The right half is shown going to the south, joined by the right lane from the west side of the roundabout, forming two southbound lanes on the vertical roadway separated by a broken white line.
