Using vehicle sensors, modern vehicles may detect roadway obstacles—such as pedestrians, potholes, objects fallen from another vehicle, etc. For example, an onboard vehicle computer may be configured to receive sensor input and, in response, control vehicle steering systems, braking systems, etc. to avoid contact or collision with such obstacles. Collision avoidance becomes increasingly difficult in situations with less response time—i.e., less time to detect the obstacle and less time for computer processing. For example, consider a first vehicle that follows a second vehicle; the first vehicle may have limited line of sight and be unable to detect an obstacle in front of the second vehicle. And if the second vehicle suddenly swerves to avoid the obstacle, the first vehicle may have insufficient time to avoid a collision therewith.