The Vehicle Emissions Prediction Model (VEPM) has been developed by the Transport Agency and Auckland Council to predict emissions from vehicles in the New Zealand fleet under typical road, traffic and operating conditions. The model provides estimates that are suitable for air quality assessments and regional emissions inventories.
Since its release in 2008, VEPM has been successfully used in Auckland and around New Zealand to estimate vehicle emissions in air quality assessments for road projects. An important feature of the model is the ability to estimate changes to vehicle emissions in future years (out to 2040).
VEPM is an Excel spreadsheet which is publicly available upon request from the Transport Agency ( environment@nzta.govt.nz ). Please add 'Vehicle Emissions Prediction Model' to the subject line of your email. A summary of the current and proposed versions of VEPM is provided below.
Version| Notes | |
| Current version of model. | |
| VEPM 5.2 | Beta version of model, which will not be formally released but is available on specific request. This version includes updates based on vehicle kilometres travelled (VKT) data from the Vehicle Fleet Emission Model (VFEM) provided by Ministry of Transport. |
| VEPM 5.3 | Anticipated release December 2016. This version will incorporate nitrogen dioxide, updates to the emission standard introduction date and country of origin assumptions, update emissions factors for Euro 5, Euro 6 and Euro V based on COPERT, and addition of Euro VI category. |
The Transport Agency has prepared a VEPM user guide which describes the modelling process and the background for the VEPM method. The VEPM user guide and a summary of the development of VEPM are provided below. Additional supporting technical information can be found in the research reports which are referenced from the user guide.
- Vehicle emissions prediction model (VEPM 5.1) user guide v1.0 - June 2013
- Vehicle emissions prediction model (VEPM) version 5.0: development and user information report - November 2011
- NZ vehicle emissions test database report - September 2013
- NZ emission factor database - September 2013
- Comparison of VEPM (model) and RSD (on-road) vehicle emission factors (CASANZ workshop presentation) - December 2013
- VEPM versus RSD comparison (National Air Quality Working Group presentation) - November 2013
- Comparison of trends in predicted (VEPM) and real-world (RSD) emissions for the light duty fleet 2003 to 2011 - December 2013
- Comparison of modelled and on-road light duty vehicle emission factors (Golder Associates) - January 2014
For further information contact environment@nzta.govt.nz .