Roadway Geometric Design: horizontal_curve_emax6
AASHTO Green Book 7th Edition (2018) roadway geometric design standards — stopping sight distance (15–80 mph), passing sight distance (20–70 mph), minimum horizontal curve radius by design speed and emax (4%/6%/8%), K-values for crest and sag vertical curves (25–80 mph), maximum grade limits by terrain type (level/rolling/mountainous) and road class (freeway/arterial/collector/local), superelevation standards, lane and shoulder width standards, and design vehicle dimensions (P, SU, WB-40, WB-62, WB-67).
| parameter type | record id | description | design speed mph (mph) | notes | unit | value min (varies) | value typical (varies) |
|---|---|---|---|---|---|---|---|
| horizontal_curve_emax6 | hc_e6_30 | Min horizontal curve radius — 30 mph emax 6% | 30 | Rmin emax=6%, f_s=0.28 at 30 mph; lower emax = larger Rmin | ft | 300 | 300 |
| horizontal_curve_emax6 | hc_e6_40 | Min horizontal curve radius — 40 mph emax 6% | 40 | Rmin emax=6%, f_s=0.23 at 40 mph | ft | 560 | 560 |
| horizontal_curve_emax6 | hc_e6_50 | Min horizontal curve radius — 50 mph emax 6% | 50 | Rmin emax=6%, f_s=0.19 at 50 mph | ft | 1,000 | 1,000 |
This is a sample. Search the full roadway geometric design dataset and 300+ more by creating a free account and accessing the database.
Get started for FREE