US Patent 7877187 Driving support method and device

A navigation device provides support for a driver of a vehicle in merging from one road onto another road (main road). The navigation device receives traffic information including at least positions and speeds of other vehicles traveling the main road. The navigation device then detects at least positions of inter-vehicle spaces between those other vehicles, using the traffic information, and determines which one of the detected inter-vehicle spaces is most suitable for the driver's vehicle to enter for merging. A beam radiating unit provided in the driver's vehicle is used to form a moving first entry point mark on the road surface to indicate the inter-vehicle space the driver's vehicle is going to enter upon merging.