Driving styles and traffic conditions (above) could make up to an 11% difference in 'greenhouse gas' emissions according to the results of an IrishCar.Com test carried out in association with Volvo Ireland.
Because that was the discrepancy in fuel consumption found between four drivers on the same route and in the same car on the test, which was carried out on a variety of roads in south Meath and west Dublin.
Carbon Dioxide emissions are directly linked to fuel consumption in any given car, and the test indicated that improvements in roads and driving habits (both are also interlinked) could go a long way towards enabling developed countries reaching the 2012 target CO2 cuts of 5% under the 1997 Kyoto protocol.
This wasn't a high-science test, just an analysis of how we each managed in fuel terms over a 22-mile course, using the on-board driving information system in a Volvo S40.
The other drivers in the test were Irish rally expert and driving teacher Rosemary Smith, the Irish Independent's motoring editor Eddie Cunningham, and IrishCar.Com news editor Trish Whelan.
The 22-mile course was selected by Rosemary Smith and included dual carriageway, country back roads, outer suburban sections, and straight country main roads.
The tests were conducted between mid-morning and mid-afternoon, and the average speed managed by each gives an indication of the traffic conditions which individual drivers encountered. Rosemary and Eddie got morning drives, while Trish and Brian had to compete with afternoon traffic.
Rosemary was able to do the course at an average 38mph, Eddie at 34mph, Trish 30mph and Brian 33mph.
Rosemary's average consumption was 38.4mpg, Eddie's 41.9mpg, Trish's 37.7mpg and Brian's 37.6mpg. The official combined average consumption figure for the Volvo S40 1.8SE is 40.9mpg.
The 11% difference between the best and the worst MPG from four experienced drivers is a really clear indication of how much difference driving conditions and habits can make to emissions from cars. If we ignore the traffic conditions, Eddie clearly has a very economical way of driving, while on the face of it mine is relatively poor. Again, Rosemary's style of working her way through her gears and her extensive experience and skills probably counted much for her better average speed while getting closer than Trish or I did to the car's own average.
The very poor roads and public transport infrastructure in the greater Dublin Area, with its resulting long queues of people in cars at standstill or in very slow mode, means a substantially increased production of the 'global warming' emissions around and in Dublin.
Put in decent roads, with less 'full-stop' intersections, and add in a proper public transport system, and we will do much more to save fuel and slow global warming from a motorists' point of view than anything else we can do.
July 2001
by Brian Byrne