
The Expert will be specific knowledgeable people at the Department of Transport, Arrive Alive Communications, the Road Traffic Management Corporation or others who might have the expertise to answer the question.
Rectangular blue signs are Reservation signs.
They mean that the area is reserved for exclusive use according to the icon on the sign (e.g. Reserved for Parking (P), Lane Reserved (R) for use by a particular type of vehicle, etc. No other vehicle type of vehicle is allowed to use that area, roadway, lane, usage, etc. So, a rectangular Reservation sign showing a motorcycle means that the area (e.g. lane) is reserved for the exclusive use of motorcycles only, and no other vehicles may drive or park there. However, motorcycles are not forced to use that area, although it has been set aside for their use for safety reasons.
Round blue signs are Command signs.
They give a definite instruction or command to the road user of what MUST be done. So, a round blue sign with a motorcycle on it means that a motorcycle rider MUST use only that area of he road way (e.g. lane) or of a parking area. S/he is not allowed to use any other area or lane. In addition, it also means that no other vehicle may use that section of the road. So, it is something like a Reservation sign. The area (lane, etc.) may be used ONLY by the type of vehicle indicated on the sign, and such vehicle MUST use that area only.