6Vehicle emissions and road layout

Design Outcome

Movement networks are designed to minimise the costs and environmental impacts of unnecessary travel.

​​​​​​​​​​​​​​The environmental impact of vehicle travel creates the greatest sustainability challenge for cities in terms of environmental damage, energy inefficiency and ongoing costs as a proportion of household income.​

Better Design Practice

  • Subdivision road networks should minimise the kilometres travelled by vehicles in the subdivision. Roads should be configured to facilitate dominant flows of traffic in and out of the subdivision.
  • Undertake a transport analysis to show the likely split between types of travel and destinations by residents of a proposed subdivision. As a part of this, calculate at least 30 years (preferably 50 years) worth of likely carbon dioxide equivalent emissions and vehicle operating expenses resulting from vehicles entering or leaving the subdivision (calculated in accordance with NZTA’s Economic Evaluation Manual, 2010). The solution proposed should lead to the least possible emissions and future costs by minimising the vehicle kilometres travelled. If it does not, clear reasons should be provided that justify this inefficiency (which could include landform or other constraints).