Roadway Geometric Design: stopping sight distance
ssd 65 to ssd 80
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) | standard | unit | value min (varies) | value typical (varies) |
|---|---|---|---|---|---|---|---|
| stopping sight distance | ssd 65 | Stopping sight distance — 65 mph design speed | 65 | AASHTO Green Book 7th Ed 2018 Table 3-1 | ft | 645 | 645 |
| stopping sight distance | ssd 70 | Stopping sight distance — 70 mph design speed | 70 | AASHTO Green Book 7th Ed 2018 Table 3-1 | ft | 730 | 730 |
| stopping sight distance | ssd 75 | Stopping sight distance — 75 mph design speed | 75 | AASHTO Green Book 7th Ed 2018 Table 3-1 | ft | 820 | 820 |
| stopping sight distance | ssd 80 | Stopping sight distance — 80 mph design speed | 80 | AASHTO Green Book 7th Ed 2018 Table 3-1 | ft | 910 | 910 |
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