This screen is used for auto generating longitudinal/braking force. Click Generate on the Loads: Load Data dialog of type LF in AASHTO standard code.

For this generation, you can select live loads specified in the program Vehicular Load library and specify the contributing length along with the number of lanes loaded. Note that as per AASHTO standard code, the braking force is determined based on lane load only. Therefore, in AASHTO standard only lane loads are available for generation. As per AASHTO, the braking force depends on axle weights as well as lane load therefore all the live loads are available for generation. Contributing length is the length of the bridge for which the loads should be generated. This is mainly used with lane load intensity. The other option allows you to specify the total live load (per lane) to use for computation of longitudinal/braking force.