1. A system for providing a travel shed indicating areas within a geographic region expected to be reachable from a specified location within a threshold period of time using a mode of transport, the system comprising: a non-transitory data store including road graph data, the road graph data indicating locations within a geographic region as nodes of a road graph and travel routes between the locations as edges of the road graph, wherein edges of the road graph are weighted based at least partly on distances between the nodes; and one or more processors configured with specific computer-executable instructions that, when executed, cause the one or more processors to at least: remove a set of nodes from the road graph to generate a reduced road graph that has a node density of under a threshold value, the node density representing a proportion of the nodes within the reduced road graph to a size of the geographic region; obtain a request for the travel shed, the request indicating the specified location, the threshold period of time, and the mode of transport; traverse the reduced road graph to determine, from at least weightings of the edges within the reduced road graph, a set of nodes, within the reduced road graph, that represent locations within the geographic area expected to be reachable from the specified location within the threshold period of time using the mode of transport; combine information regarding the set of nodes within reduced road graph to form the travel shed indicating areas within the geographic region expected to be reachable from the specified location within the threshold period of time using the mode of transport; and generate an indication of the travel shed.