To continue the story, this second article details the evolution of AASHO
and its successor, the American Association of State Highway and Transportation Officials (AASHTO), as the premiere voice of transportation officials around the country.
The Present Serviceability Index (PSI) is based on the original AASHO
After that, AASHO
continued to work on improving the Interstate Highway System, by developing and updating the geometric design standards for the new Interstate.
With the founding of AASHO
, all of the pieces were in place to create the Federal-aid highway program.
then proposed additional research on pavement performance to overcome the road test's limitations but never implemented these further studies, partly because the engineers of the day believed that advances in pavement engineering theory and mechanistic modeling would be able to fill the gaps.
considered the proposal, the named-trail associations lobbied for changes.
gathered in December 1962 for its annual meeting, Whitton included a challenge for State highway officials in his annual speech.
The initial reaction of State highway officials is reflected in a speech by AASHO
President William A.
The empirical equations used in the 1993 AASHTO guide are largely a result of the original road tests performed by AASHO
from 1958 to 1961, in what was the largest experiment on highway pavements of its time.
The estimate assumed that a substantial portion--nearly 11,270 kilometers (7,000 miles)--would need only two lanes to provide adequate service, but under the higher standards developed by AASHO
and the BPR, most segments would be four lanes except in sparsely settled portions of the West.
and NCSHS have become AASHTO (American Association of State Highway and Transportation Officials) and NCUTCD, but their missions are still the same.
Later in 1918, Hirst would become the fourth president of AASHO