For those roads where the AADT is greater than 1,500 vehicles per day, the arrangement and spacing of edge marker posts on horizontal curves should:
Table 3‑7: Edge marker post spacing table for rural roads with AADT greater than 1500vpd
| Horizontal alignment | Retroreflector type for curve direction (see note 1) | Spacing (m) | Post location | |||
|---|---|---|---|---|---|---|
| LH curve | RH curve | |||||
| Left | Right | Left | Right | |||
| Curve radius less than 30m | A | C | A | B | 10.0 | Pairs opposite |
| Curve radius 30 - 40m | A | C | A | B | 12.5 | Pairs opposite |
| Curve radius 40 - 60m | A | C | A | B | 15.0 | Pairs opposite |
| Curve radius 60- 80m | A | C | A | B | 17.5 | Pairs opposite |
| Curve radius 80 - 100m | A | C | A | B | 19.0 | Pairs opposite |
| Curve radius 100 - 150m | A | C | A | B | 21.0 | Pairs opposite |
| Curve radius 150 - 200m | A | C | A | B | 25.0 | Pairs opposite |
| Curve radius 200 - 300m | A | C | A | B | 28.0 | Pairs opposite |
| Curve radius 300 - 400m | A | C | A | B | 31.0 | Pairs opposite |
| Curve radius 400 - 600m | A | C | A | B | 35.0 | Pairs opposite |
| Curve radius 600 - 800m | A | C | A | B | 40.0 | Pairs opposite |
| Curve radius 800 - 1200m | A | C | A | B | 45.0 | Pairs opposite |
| Curve radius over 1200m | A | B | A | B | 50.0 | Pairs opposite |
|
Straights; refer note 1 |
A | B | A | B | 100.0 | Pairs opposite |
Table 3‑7 notes:
Table 3‑8: Minimum radius of curvature for straights
| Design Speed (km/h) | 30 | 40 | 50 | 60 | 70 | 80 | 90 | 100 | 110 | 120 | 130 |
|---|---|---|---|---|---|---|---|---|---|---|---|
|
Minimum Radius (m) |
200 |
350 |
550 |
800 |
1100 |
1500 |
1900 |
2400 |
3000 |
3700 |
4500 |
The radius of a curve at any given point is a function of whether the alignment is in a spiral transition or is part of a fully circular curve. As the curve radius decreases through the approach transition, the spacing of edge marker posts will also decrease until the fully circular portion of the curve is reached and the curve radius is constant. The opposite applies on the departure transition in that as the curve radius at a point increases, the spacing of edge marker post will also increase.
Figure 3‑7: Edge marker post installation on all rural state highways and other rural roads with AADT greater than 1,500vpd – Left hand curve
View larger image [JPG, 1.9 MB]
Figure 3‑8: Edge marker post installation on all rural state highways and other rural roads with AADT greater than 1,500vpd – Right hand curve
