A secondary factor is related to individual drivers. Whether or not you believe the official combined fuel consumption figures for cars is an accurate reflection of what company car drivers should be achieving, it can sometimes bring tears to the eyes when vehicles appear to be averaging 10-20mpg less than expected.
RAC Business Solutions claims that with the right attitude, drivers should be able to achieve a 30% improvement on the official figures, while still driving sensibly and safely.
It attempted to demonstrate this view when it held five fuel economy marathons throughout the UK.
Fleet News was keen to take part in the event and, as I had already achieved something of a record in one of our long-term test cars two years ago, I was volunteered.
During the dreaded fuel protests of September 2000, I was driving our long-term Mazda 626 2.0 Sport and managed to squeeze a remarkable 52.8mpg from the car between refills. This was a 51% improvement on the official combined figure of 34.9mpg.
The RAC Business Solutions events were held in Bristol, Birmingham, Manchester, Chesterfield and Bourne End, Buckinghamshire.
I attended the Bourne End event and was the first participant to arrive at the RAC's headquarters. I was told I would be going out first and needed to select a navigator from the RAC Business Solutions' team.
Chris Reynolds, marketing director of RAC Business Solutions, was already on the route to set a benchmark figure, as was the RAC's fuel economy guru Jack Clarke. The challenge was to travel as far as possible on our set route until we had used half a gallon of fuel according to the on-board computer. At that point the mileage and the average fuel consumption would be recorded.
Reynolds returned from the rush-hour traffic with an average of 44mpg while driving normally. Clarke had already been out and came back with an average of 56mpg. RAC staff were confident that 56mpg could be bettered as traffic became lighter. I had driven with Clarke in the passenger seat before – about two years ago when I did a feature on driver training and risk management. I asked if he could be my navigator on the route, hoping he might offer a few tips as we were driving.
The Bourne End event followed routes around Marlow and Henley and involved more challenging roads than people would normally encounter in everyday driving. There would probably be no point in including motorways and major roads where you can travel for miles without stopping.
Everyone in the event drove Vauxhall Vectras fitted with 2.2DTi turbodiesel engines and manual gearboxes, with an official combined fuel consumption figure of 43.5mpg.
We were warned by Clarke that we should drive safely – no coasting downhill or holding up following traffic – and with those words ringing in our ears we set off with a few minutes' interval between each car.
The air conditioning had been switched off from the start - which can lead to a fuel consumtpion improvement of up to 7%.
The 45-mile route should have taken between 60 and 90 minutes, depending on speed and how soon the driver used up the half-gallon, according to monitoring equipment in the car.
The first few miles were painfully slow and I was surprised by the amount of effort and concentration it took to question every instinctive movement as I travelled along. I had to select the ideal point for changing up through the gears earlier than normal but without labouring the engine.
The first 20 minutes or so saw the trip computer hover just below the 40mpg mark and the Vectra's flow was stilted by urban traffic. Things improved out of town, and it wasn't too long before 50mpg appeared. I switched off the engine at one set of traffic lights when the one-way traffic and lengthy delay made it easier to anticipate when the lights would turn to green.
My high point came when the trip computer flashed up 56.3mpg and I thought there was a good chance of sewing up the win on the remainder of the route.
Then, just around the next bend, we were faced with a seemingly interminable hill. Clarke said: 'My heart sank when I saw that on the route this morning. I had been doing 58mpg until then.'
We reached the 0.5 gallon point at 27.6 miles (and 55.2mpg) – a 27% improvement on the official figure.
By this time one of the following cars had become visible in the rear-view mirror. I was certain this would be one of the highest results on the day, despite my bad luck with traffic and having to stop at round-abouts to give way to other traffic on the right ('There's always one,' Clarke said).
However, racing driver Ed Redfern achieved the highest fuel economy on the day – a remarkable 64.8mpg (a 55% improvement on the official figure), considering he was a self-confessed fuel economy novice.
Also taking place during the week was a competition that pitted RAC bosses against their PAs on the fuel economy courses. After four events the two teams were tied, but on the last day, John Ascroft, head of risk services, just managed to beat his PA to clinch the win for the bosses.
Despite this, the best individual fuel economy figure was recorded by a PA, Fiona Apsley from RAC Business Solutions in Chesterfield.
Ascroft said: 'We could all do with saving money on fuel costs, especially with the threat of more price rises. Our challenge was a fun way of showing how a few simple driving tips can make a big difference to your fuel consumption.'
|RAC Business Solutions' mini-mpg regional marathon|
|Warren Jones:||Vauxhall Master Hire Bristol||67.4|
|Fiona Apsley||RAC Business Solutions Chesterfield||65.0|
|Dave Moss||freelance broadcast journalist Birmingham||65.0|
|Ed Redfern||Zip formula driver Bourne End||64.8|
|Helen Tither||Manchester Metro News Manchester||60.6|
Top tips for frugal driving