... then the "final" Virginia section, Arlington Boulevard, with its mysterious 8 ton truck weight limit (nobody I have talked to seems to know the origin of that limit) and merging with I-66 as it crosses into D.C.
You have now talked to the right person...
The restriction was enacted Sept 23, 1937 (pg 28 at http://www.ctb.virginia.gov/meetings/minutes_pdf/CTB-09-1937-01.pdf) from Falls Church to Fort Myer
"not sufficiently strong to carry heavily weighted trucks."
Pg. 29 of the March 1950 CTB (http://www.ctb.virginia.gov/meetings/minutes_pdf/CTB-03-1950-01.pdf) noted that the exact boundary of the truck restriction was not well defined so here they made it explicit from VA 237 Ft Myer west to the Fairfax Circle.
US 50 was officially put onto Arlington Blvd in Aug 1937 and it was new construction, so it is curious and unfortunate it was unable to handle truck traffic as it existed in the 1930s.
The Dr. Gridlock article reads to me that while the road is old, the truck restriction is a recent development.
That's really fascinating. I remember U.S. 50 having a weight restriction as far back as the 1960's (I have mentioned in this forum going to visit an aunt and uncle that lived in the Lake Barcroft area of Fairfax County), and our route would cross U.S. 50 (Arlington Boulevard) at some point on the way there.
I am speculating now, but I wonder if the original construction might have been done by the federal government (maybe to improve road access to Fort Myer) and then turned-over to State Highway Commission/Virginia Department of Highways? I have a
hard time believing that VDH (or its predecessor, SHC) would have allowed the construction of such a substandard road with state dollars.
I know that much of Arlington Boulevard has an "old" feel to it, though the limits above do raise a question. Buses have apparently
never been restricted (including chartered buses, school buses, and
especially transit buses (Arnold Lines prior to about 1964, then D.C. Transit's Virginia subsidiary, W.V.&M. "Virginia Lines," and since 1972 WMATA's Metrobus and in some places probably ART and Fairfax Connector)). The transit buses run by Arnold Lines, W.V.&M. and WMATA were quite a bit heavier than 8 tons, and generally
very heavy in the rear over the drive axle.
I assume that those drive axle loadings would be very hard on the pavement, but apparently not that much.