Managing speed and modes Print

Design Outcome

Subdivision design ensures the safety of pedestrians and cyclists by managing vehicle travel speed, and provides equally for the four major modes (walking, cycling, passenger transport, vehicles) in a way that will appeal to the users of each.

​​​​​​​​​​​​​​​​​Despite the economic benefits of having the shortest possible journey times for the movement of goods and services, fast-moving free-flow traffic also brings major safety and amenity problems that can only be addressed by restricting pedestrian and cyclist use of the road. 

This action can be fair on busy arterial and collector roads in peak times, but is not appropriate on local roads or in inter-peak periods.​​​​​​​​

Better Design Practice

  • Street design provides a signal of what speed a vehicle should be travelling, through elements such as road width and landscaping.
  • Roads should not be over-designed for vehicle safety with features such as wider than necessary travel lanes or corners. ​
  • Over-design, often based on concern for vehicle occupant safety, can unintentionally result in drivers concentrating less (a phenomenon known as 'driver automation') or increasing their travel speed. Therefore, roads should be designed based on a balance of safety and amenity for all users, not just for vehicle occupants.​​
  • Pedestrian and cyclist safety comes first when deciding on elements such as street trees, islands or berms. Speed reduction devices, safe and logical crossing points and easy routes that directly follow desire lines will also contribute to pedestrian and cyclist safety​.
  • Streets should be designed to encourage the lowest possible vehicle speed for the use of the road, based on the importance of the road in the road hierarchy. Low speeds can be achieved by: 
    • geometric design and curve radii
    • managing sightlines and long straight links
    • reducing the width of the vehicular travel lanes
    • using a variety of textures and surfaces
    • using flush medians only on very busy streets
    • promoting slow speeds at intersections and road entrances

  • Design intersections and the beginning section of each street in a way that slows vehicles down to an appropriate speed from the start, rather than further along the street. Landscaping should be integrated into such thresholds.
  • Traffic-calming tools include:
    • using different materials, textures or colours to make vehicular carriageways, footpaths, cycle ways, parking bays and manoeuvring areas clearly legible
    • 'tightening' intersection corners to ensure slower vehicle movements 
    • incorporating islands or raised berms to help pedestrians cross and slow vehicles down
    • avoiding long stretches of straight local residential roads by using the road reservation width to allow for regular bends or 'shifts' in the carriageway  
    • incorporating chicanes at key points to slow movement. The use of mountable kerbs can allow more space for large and emergency service vehicles 
    • incorporating landscaping into parking bays to help make the carriageway seem narrower to drivers 
    • developing tables (essentially large, flat speed humps) with material differentiation to aid pedestrian crossing without relying on formal crossing points 
    • raising intersections and using different materials to make these points more prominent, while helping to slow vehicles down
    • speed bumps or humps are the least desirable form of intervention for traffic calming.

  • Design higher-density subdivisions carefully to avoid a high number of vehicle crossings passing over the footpath, and to maintain the level and flatness of the footpath.
  • The amenity and sense of character, or 'place', of streets that people live along is essential to successful and liveable subdivisions. The predominance of vehicles in street design (including the number of travel lanes) and high vehicle speed are the biggest risks to establishing and maintaining this amenity.

Rules of Thumb

1. Design to achieve lower maximum speeds on all local roads, with the speed reflecting the function of the road. The lowest design speeds should be used on very quiet roads. For example 40km/h maximum speed might be appropriate on local roads, whilst a 30km/h maximum speed might be appropriate on very quiet roads.

Economic and social impacts result from pedestrians not being able to easily cross a street and from a loss of amenity when vehicle numbers and speeds increase.

2. Consider having separate cycle lanes on appropriate roads, where there are high vehicle speeds and where there is the opportunity for creating a connected network of cycling infrastructure. Early discussion with Auckland Transport is required.

These can be either 'on road' next to the vehicle travel lane or 'off road' next to the footpath. Where the vehicle speed is lower than 40km/h, cyclists should be able to safely share the road with vehicles and feel comfortable. Low-speed shared vehicle and cycle lanes also allow cyclists to travel two-abreast instead of single file.

3. Vehicle crossings (driveways) should be as narrow as possible for every lot, to reduce vehicle entry and exit speeds.

This will ensure that streets and footpaths are not dominated by vehicle access, and will limit interruptions to pedestrian amenity. It also ensures there is sufficient street space for street trees and on-street parking bays.
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