> For the complete documentation index, see [llms.txt](https://docs.openbrim.org/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.openbrim.org/templates/openbrimfea/loads-fea/live-loads-fea.md). # Live Loads \[FEA] Live Loads holds the objects used for influence-surface traffic loading. **Vehicles** define axle configurations. **Design Lanes** define a traffic lane - its width, the vehicles that travel in it, the accompanying lane load, and the rules for placing vehicles within it. **Influence Surfaces & Lines** define the loaded region and the grid of unit-load positions used to build the influence coefficients. **Live Load Cases** tie the lanes and surfaces together and run the search. The analysis places a unit load at every grid point, solves, and then searches for the vehicle and lane arrangement that maximizes each response. Results are therefore **envelopes**: each value is the worst case over all positions, and different values correspond to different truck positions. They are not a single equilibrium state, and pairing two enveloped maxima for an interaction check combines actions that never coexist. Grid spacing is the main trade-off: finer grids find sharper peaks, at a cost that grows quadratically. --- # Agent Instructions This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com. ## Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter, and the optional `goal` query parameter: ``` GET https://docs.openbrim.org/templates/openbrimfea/loads-fea/live-loads-fea.md?ask=&goal= ``` `ask` is the immediate question: it should be specific, self-contained, and written in natural language. `goal` is optional and describes the broader end goal you are ultimately trying to accomplish on behalf of the user. GitBook uses it to tailor the answer towards what is most useful for that goal. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.