In this scenario, do you have priority over the vehicle on your left that is going straight through the intersection?

In the video you are driving along a residential street and approaching a T-junction; on the right there is sign D-1 "priority road" with plate T-6a, on which the thick line turns left and the thin one goes off to the right; a light-coloured car going straight on is approaching from the left. You have right of way over it. The answer is: yes.

The Regulation on road signs and signals states that sign D-1 marks the beginning or continuation of a priority road, and plate T-6a shows its actual route through the junction. The thick line runs from you and turns left - this means that your road and the road from which the car on the left is coming are the same priority road; only the entrance on the right is a minor road. The Road Traffic Act states that a driver approaching a junction gives way to a vehicle approaching from the right - and exactly this rule applies between vehicles travelling along the priority road. For the driver on the left you are the vehicle from the right, so he gives way to you. When approaching the junction, you slow down anyway and make sure that the driver on the left is really letting you go.

Legal basis: § 43 para. 1 and 2 of the Regulation on road signs and signals; Art. 25 para. 1 and Art. 4 of the Road Traffic Act (Prawo o ruchu drogowym)