Key legal question
Whether the appellant could rely on the trust principle when turning left after signaling, despite not checking behind.
Extracted holding
No. A left-turning driver may rely on the trust principle only if he has clearly and unmistakably indicated the maneuver, including proper positioning where possible; in an unclear situation he must additionally secure himself to the rear.
Extracted reasoning
Because the road was snow-covered and the center line was not visible, the appellant could only approximate the lane position. That created an uncertain situation for following drivers and required heightened caution. Failing to look back violated Art. 34(3) and 39(2) SVG.