Values by Design Speed
Stopping Sight Distance
| Design speed (km/h) | Design speed (mph) | Design SSD (m) | Design SSD (ft) |
|---|
Green Book Table 3-1 [1], level roadways, metric (the source unit; mph and ft are exact conversions, not the US customary table). Brake reaction time 2.5 s, deceleration 3.4 m/s².
Side Friction Factor & Minimum Radius
Maximum side friction factor f from Green Book Table 3-7 [1] (metric). Radii are calculated from the point-mass formula R = V²/[127(e/100 + f)], unrounded; Table 3-7 also lists rounded design values.
Vertical Curve K Values
| Design speed (km/h) | Crest curve K | Sag curve K | ||
|---|---|---|---|---|
| m/% | ft/% | m/% | ft/% | |
Design K (length per percent of algebraic grade difference, L = K·A) for stopping sight distance, Green Book Tables 3-34 (crest) and 3-36 (sag) [1], metric; ft/% are exact conversions.