Modelling the potential impact on CO2 emissions of an increased uptake of active travel for the home to school commute using individual level data
Nick Bearman; Alex D. Singleton (2014). Journal of Transport & Health, 1(4), 295-304. DOI: 10.1016/j.jth.2014.09.009
Abstract
Active travel for the home to school commute is an ideal opportunity to improve pupil’s physical activity levels. Many studies have looked at how pupils travel to school and the motivating factors behind these decisions. This paper applies an innovative methodology to model each pupil’s individual route to school and then evaluates how different policy changes could increase the uptake of active travel. The changes are quantified in terms of the proportion using active travel, CO2 emissions and criterion distances: a method of measuring how far pupils are willing to travel using a certain mode of transport. Findings suggest that the greatest reduction in CO2 and increase in health benefits can be made by encouraging more primary school pupils to use active travel and targeting schools with existing low levels of active travel.
Extended Summary
This research investigates how different policy interventions could increase active travel (walking and cycling) for school journeys and reduce associated CO2 emissions. The study addresses a pressing public health concern, as active travel levels among school pupils have declined significantly over the past 40 years, contributing to reduced physical activity and increased environmental pollution. The research uses an innovative geographic information system (GIS) methodology to model individual pupil routes between home and school across Norfolk, a predominantly rural English county with 435 primary schools and 77 secondary schools serving 54,383 pupils. Rather than relying on traditional sampling approaches, this work models actual routes for every school child in the dataset, accounting for different transport modes and local geographical variations in vehicle emissions using Driver and Vehicle Licensing Agency (DVLA) data. The methodology was validated against GPS-recorded journeys from the SPEEDY study, showing strong correlation (R²=0.78) between modelled and actual route distances. Three policy scenarios were tested: a general increase in active travel across all schools, targeted walking bus schemes for primary schools (reducing car use by 20% for journeys under 2km), and focused interventions at the 20% of schools with lowest active travel rates. The study introduces criterion distances - the maximum distance that 85% of pupils are willing to travel using a particular transport mode - as a key measurement tool. For Norfolk primary schools, criterion distances were 1.5km for walking and 2.0km for cycling, whilst secondary schools showed higher thresholds of 2.5km for walking and 3.0km for cycling. The research found that all three scenarios significantly reduced CO2 emissions, with the most substantial reductions occurring in urban areas where shorter distances make active travel more feasible. The walking bus scenario achieved a 13.2% reduction in CO2 emissions for primary schools, whilst the targeted approach proved nearly as effective as universal interventions (11.7% versus 11.5% reduction), suggesting that focused strategies could deliver similar environmental benefits at lower implementation costs. The findings demonstrate that encouraging active travel among primary school pupils offers greater potential for both environmental and health improvements compared to secondary school interventions, due to shorter average journey distances. This work provides a robust methodological framework for evaluating transport policy impacts that could be replicated across different geographical contexts and scales of implementation.
Key Findings
- Targeted interventions at schools with low active travel rates achieve similar CO2 reductions (11.7%) to universal approaches (11.5%) at lower cost
- Primary school pupils show greater potential for active travel adoption with criterion distances of 1.5km walking and 2.0km cycling
- Walking bus schemes could reduce CO2 emissions by 13.2% for primary schools through 20% car use reduction for journeys under 2km
- Urban areas demonstrate highest potential for emissions reduction due to shorter average distances between homes and schools
- Individual route modelling provides more accurate policy impact assessment than traditional sampling or straight-line distance methods
Citation
@article{bearman2014modelling,
author = {Nick Bearman; Alex D. Singleton},
title = {Modelling the potential impact on CO2 emissions of an increased uptake of active travel for the home to school commute using individual level data},
journal = {Journal of Transport \& Health},
year = {2014},
volume = {1(4)},
pages = {295-304},
doi = {10.1016/j.jth.2014.09.009}
}