Has the TTMA-100 been crash tested with an arrow board and approved by FHWA? What happens to the arrow board upon impact?
The TTMA-100 has not been crash tested with an arrow board and STI has not sought FHWA approval. The support for an arrow board or variable message sign (VMS) is subjected to impact loads only when the TTMA-100 and the support truck are accelerated forward during a crash. All crash tests of the TTMA-100 were conducted with the support truck blocked to simulate an infinitely heavy vehicle. Hence, the TTMA-100 was not subjected to high accelerations that would cause problems for an arrow board or VMS. However, using the highest sustained accelerations measured during the pickup truck end-on test (test 3-51), design loads for the TTMA-100’s sign mounting system were determined. This maximum acceleration was converted to an equivalent force that was then applied to the lightest allowable support truck and trailer combination, a 10,000-lb support truck with a 1,400-lb trailer. The trailer acceleration resulting from this level of applied force was then used as a design load when analyzing t
