The American Association of State Highway and Transportation Officials recently released the 7th edition of its “Policy on Geometric Design of Highways and Streets” manual – commonly referred to as the “Green Book” – which is considered by many to be the pre-eminent industry guide to current highway and street design research and practices.
AASHTO said the latest edition of the “Green Book” presents an updated framework for geometric design that is more flexible, multimodal, and performance-based than in the past – providing guidance to engineers and designers who strive to make unique design solutions that meet the needs of all highway and street users on a project-by-project basis.
The group noted that not only are “traditional” functional classifications for roadways – such as local roads and streets, collectors, arterials, and freeways – contained within the Green Book, but so is an expanded set of new “contextual” classifications – such as rural, rural town, suburban, urban, and urban core – that will help better guide geometric design efforts.
On top of that, AASHTO said the first chapter of the new manual – entitled “New Framework for Geometric Design” – also introduces a “new approach” in terms of how functional and context classifications can be used together to create more “flexible and performance-based” designs for new projects as well as for existing roads.
[A list of key revisions and updates to the new manual are available at: http://downloads.transportation.org/publications/GDHS-7_SummaryOfChanges.pdf.]
The “Green Book” is available to order in hard copy or as a downloadable PDF from the AASHTO Store at: https://store.transportation.org/item/collectiondetail/180. It can also be ordered at a discounted rate when purchased in a set that includes both the hard copy and downloadable PDF versions, the group noted.