Well, I think there might be a reason for the speed limit in Hk gei, as even thought the TD claimed that the road is up to international standard, but as I've driven in HK alot of times, I feel that some trunk road should not exceed their speed limit due to the poor design of the road, this is also a similar situation in Singapore too. (BTW: I've always drive over speed limit in US/ CAN, but I rarly does that in HK, not because of afraid to get ticket, but it's because of safety reason)