Transportation & Surveying Calculators

This category is really two toolkits that share a job site. The design half implements AASHTO methods: flexible pavement via the 1993 Guide's structural number equation and layer coefficients, rigid pavement via the corresponding slab-thickness solution with load-transfer factor J, stopping sight distance from the Green Book's reaction-plus-braking model with grade correction, and vertical and horizontal curves — K values, crest and sag criteria, and the full curve geometry set (T, L, E, M, LC and PC/PT stationing). Traffic flow capacity rounds it out with the Greenshields speed-density model and its capacity point.

The surveying half is the classic COGO trio. Area by coordinates runs the shoelace formula with centroid and winding direction; traverse closure computes latitudes and departures, linear misclosure, and distributes the error by Bowditch adjustment; and bearing & distance solves both the inverse problem (two points to an azimuth and distance) and the forward problem, in bearings or DMS azimuths. These are the checks a plat or a closed traverse either passes or does not — the calculators show the intermediate columns so a bust is traceable to a leg.

Asphalt tonnage bridges design and construction: area times compacted thickness times density presets to short tons or tonnes, with truckload counts — the number the paving foreman and the estimator both need from the same pavement section the AASHTO tools produced.