2. Not disallowed, only the functionality  
3. Signage would be an additional criteria, but not required/necessary. You have to consider the simplicity of signage, and encouraging you to use NCWBR, but that only means NCWBR should be `=primary` , not bypassed CWBR can't be `=secondary` . Eg airport is signposted via Tsing Sha Hwy in Shatin, but majority or at least significant minority would use Shing Mun Tunnels, and I would argue this should be considered in classifying Tsing Yi N Coastal Rd — Tsing Tsuen Rd (besides how it connects with Route 5). 