2-2Vertical Alignment

Vertical alignment design covers grade selection, vertical curves, and sight distance. Maximum grades are determined by terrain classification and design speed per AASHTO Green Book Table 3-3. MassDOT maximum grades: Level terrain 3-5%, Rolling terrain 4-7%, Mountainous terrain 6-10%. Crest vertical curves require minimum K-values for stopping sight distance. Sag vertical curves require minimum K-values for headlight sight distance and rider comfort (A/46.5).

References: AASHTO current edition, MA Standard Specifications, FHWA Technical Advisories, and applicable federal regulations (23 CFR). Contractors shall maintain current copies of all referenced standards on the project site.