Flood agrees: “Alternatively-fuelled vehicles may be harder to reallocate to staff.”

Not sticking to a single fuel type also adds complexity, according to Chandler.

“You need to understand the products,” he says. “In the past there might have been three petrol engines to choose from and three diesels, for example, but now it’s much more complex. There is more to consider.”

Baxter adds: “It must be made clear to employees which type of vehicle is most suitable for their usage.”

Mileage reimbursement should also be a consideration.

Fisk says: “It can make reimbursement difficult if fuel types are run with different rates – often the case when using Advisory Fuel Rates.”

Misfuelling could become an issue if a company car driver has had a diesel for many years and switches to petrol or if cars are shared among employees.

However, Chandler argues that this alone is not a reason to stick to a diesel-only policy.

It is worth analysing fuel consumption figures when deciding which fuel type is best.

“The analysis of data Allstar collects confirms that drivers struggle to achieve manufacturers’ fuel consumption figures,” says Flood. “This is especially true with alternatively-powered vehicles.”

In some respects this comes back to vehicle application.

Alternatively-powered vehicles that are not achieving the expected fuel economy may not be being used
in the right environment or driven in an eco-friendly manner.

Ultimately, fleet operators need to decide whether they want to adopt the easiest policy – a blanket approach with diesel-only – or whether they are prepared to use wholelife costs and do the analysis required to work out the most cost-effective fuel type for different driver populations.

Pros and cons of diesel-only versus mixed-fuel policies

Pros

  • Easy to administer
  • Allows a single mileage reimbursement rate to be used
  • Suits high-mileage drivers who do regular motorway journeys
  • Generally suits the company car tax regime

Cons

  • Restricts driver choice
  • Could prove more expensive for low-mileage drivers
  • Diesel particulate filters can cause an issue with predominantly urban use
  • Not as environmentally-friendly as other options
  • Diesels generally have a higher purchase price than petrols
  • Diesels have a 3% benefit-in-kind tax surcharge until 2016/17