Zero-shot road segmentation with foundation models

What foundation models like SAM and CLIP got right on road scenes without labelled training data, where they failed, and how we measured it at Continental.

A country road winding between green hills
A country road in the Lake District.

Training a road segmentation model usually starts with thousands of labelled images. At Continental, the question was whether foundation models could find the road with no task-specific training at all.

The approach

Segment Anything proposes masks for everything in the frame. A text prompt scored with CLIP decides which of those masks is road. SEEM handled the scenes where a single prompt was not enough.

What worked

The zero-shot pipeline reached 99% precision. That was enough to use its masks as pre-labels for the annotation team, which cut labelling costs by 70%.

What didn't

Wet roads, strong shadows and road edges without markings were the hard cases. Those are exactly the scenes a driver-assistance system cares about most, so they went to people, not to the model.