This document describes techniques and systems to make determinations of lane-type and roadway hypotheses in a road model. The road-perception system can fuse various forms of evidence to determine lane-type hypotheses and respective belief masses associated with the lane-type hypotheses. The road-perception system the computes, using the belief masses, a belief parameter and a plausibility parameter associated with the lane-type hypotheses. One or more roadway hypotheses are then determined using the lane-type hypotheses. The road-perception system then uses the respective belief parameter and plausibility parameter associated with the lane-type hypotheses to compute a belief parameter and a plausibility parameter associated with the roadway hypotheses. In this way, the described techniques and systems can provide an accurate and reliable road model with quantified uncertainty.