Salam Mr Harjit Singh Sir,
As seen in the notes below,
For federal road, its speed limit is 90km/h.
During festive season its reduce to 80km/h,
In town area, reduce to 60km/h.
A simple logical explaination to your question is, though separate designated lanes are provided for motorcycles, but still the volume of cars, lorries (which contribute to p.c.u) determines the speed.
There may be designated motorcycle lane, but the no of motorcycle is nil, but volumes of cars and lorries is tremendous, dun tell me v r gonna reduce the speed limit?
If we were to refer arahan teknik jalan, there are actually lot of factor that determines the speed.
Among others are, type of road R1,2,3,4,5,6, U1,2,3,4,5,6 expressway, width of road, condition of road whether its mountanious, rolling, volume of traffic. Its all been spell out.
Food for tot, if the width of road is a constraint, by introducing designated motorcycles lanes, indirectly u are narrowing the lanes for cars and lorries( i am referring to existing roads where road width is very very limited) . Therefore when volumes maintain the same or higher but lanes becomes narrower, more so why we need to reduce the speed.
اللهمّ يسر و لا تعسر
Had Laju Kebangsaan (National Speed Limits) is a set of speed limits applicable on Malaysian expressways, federal roads, state roads and municipal roads. The National Speed Limits was enforced on 1 February 1989 following the National Speed Limit Orders 1989 (Perintah Had Laju Kebangsaan 1989). Like any other countries in the world, failing to obey the speed limit on Malaysian roads and expressways is an offence as subject to Malaysian Road Safety Act 1987, which can be fined up to RM300, depending on the difference between the speed limit and the driven speed.
Default speed limits
Expressways: 110 km/h (68 mph) by default, but may be reduced to 80 or 90 km/h (50-56 mph) at dangerous mountainous stretches, crosswind areas and urban areas with high traffic capacity.
Federal roads: 90 km/h (56 mph) by default (reduced to 80 km/h during festive seasons), 60 km/h (37 mph) in town area.
State roads: 90 km/h (56 mph) by default (reduced to 80 km/h during festive seasons), 60 km/h (37 mph) in town area.