Posting vs designing a speed limit

WalkSydney recently discussed 30km/h advocacy and the balance between posting a speed limit and designing a speed limit.  

This short video compares traffic calming in Canada to traffic calming in the Netherlands. (NSW uses a similar Warrants system to Canada).

The video also explains Level of Service for vehicles which exists in NSW. WalkSydney is advocating for Level of Service to include the movement of people in general.

The video highlights the importance of road rules (and guidelines) in supporting slower road speeds.

“Humans will make mistakes, so roads are designed to protect people and be consistent, to make it easier to do the right thing….without being explicitly told to do so.”

Video at 3:45

BIKESydney writes in response to our blog post about North Sydney Council’s recent focus on pedestrian safety:

Achieving these improved walking (and cycling) outcomes, will depend necessarily on road geometries being amended. It won’t be enough to merely sign-post lower speed limits, for example. It may be that geometry interventions need to be staged over time (that’s OK), but it’s essential that these interventions be included. Merely erected 40 km/h signposts generally doesn’t work, as shown in the CBD (eg Wentworth Ave). The type of intervention will be different for different road setups, but could include, kerb buildouts, vehicle lane narrowings, chicanes, raised thresholds, reduction in corner kerb radii, new pedestrian medians, road closures (at one end for example; not all streets need be available to through traffic) and separated cycleways.  

What do you think? Is it the posted speed (which can be ignored) or the design of the streets (which is much harder to ignore) what WalkSydney should advocate for? In some places, or most places?