May any vehicle stop in a lay-by marked in this way in order to drop off a passenger?

The D-15 sign visible in the photo indicates a bus stop located in a bay. According to Art. 49 para. 1 pt. 9 of the Road Traffic Act, an absolute prohibition on stopping applies along the entire length of a bus bay. This regulation does not provide for an exception for dropping off passengers, so you cannot enter and stop your vehicle there.