Quote Originally Posted by Honky Tonk View Post
I know. It was a joke. Who did you survey for? I did it for years for MDSHT. The tapes we used, [[back then) were of a certain thickness which, supposedly, took temperature changes into account, and wouldn't "adjust". On roads, it didn't matter much. On bridges, you wanted to be as accurate as possible. I think the GP bashing around here borders, [[speaking of which) on lunacy.
In 1959, I ran the survey party for the then new and sparsely settled City of Troy. The correction in length for temperature changes of a flat steel tape is:

C=0.0000065[[Tt-T)L

where C is the correction, Tt is the ambient temperature, T is the baseline temperature [[68F), and L is the standard length [[100ft)

ETA: The old standard when you fudged a closure was "close enough for highway work".