I'm doing a hand check of shear at midspan of a single span bridge (L = 142'). Loading is AASHTO LRFD HL93. Based on my calculations, the shear with impact should = 42 kips. However, Conspan reports 52.9 kips. Note that I manually input a distribution factor of 1.0 so I could easily compare. Am I missing something with the load application? Or with another factor that Conspan may be applying?