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Fleet management toolkit

Manage business travel and grey fleet use

Reducing and managing grey fleet should be a priority for organisations, both from an environmental and cost perspective. Numerous cost-effective and convenient options exist.

Why is ‘grey fleet’ mileage a problem?

‘Grey fleet’ refers to vehicles that are privately owned or leased by employees but used for business travel. In many organisations, grey fleet mileage is unnecessarily high. On average, grey fleet vehicles are older, less safe and more polluting than alternatives, such as company or pool cars. Energy Saving Trust and BVRLA estimate that employees drive over 12 billion miles each year, costing employers around £5.5 billion a year, contributing to congestion, air pollution and emitting 3.5 million tonnes of carbon dioxide.

There are also duty of care implications. The law is clear – an organisation has a legal duty of care to an employee, regardless of vehicle ownership, which means grey fleet needs to be managed as diligently as company-owned or leased vehicles. For more detail on duty of care and health and safety implications, see our guide to managing grey fleet mileage.

Making grey fleet the last resort for staff is also likely to result in substantial savings for an organisation, as alternatives – such as daily hire vehicles – can be more cost-efficient. Proactive grey fleet management also tends to be associated with reduced mileage and therefore reduced costs and higher productivity.

For more detail, see Drivers for change (in Process, drivers, considerations and monitoring).

To help finding the breakeven point, see Daily car rental vs private car costs spreadsheet.

Establishing responsibilities

Managing grey fleet can be challenging and requires numerous teams to collaborate. One reason grey fleet is often overlooked is that no one is responsible for its overall management. In some organisations, the fleet manager might assume responsibility, but an individual could also be appointed from finance or HR.

It can be helpful to establish a working group to assist with developing and implementing a grey fleet policy, especially for a large fleet or public sector organisation.

See the Stakeholder engagement matrix for help in identifying who should be involved and how. Our guide to managing and reducing grey fleet mileage also offers some tips to help overcome barriers (see p13).

This Cabinet report may be useful when presenting to a local authority committee or building a business case for action.

Understanding the characteristics of grey fleet journeys

Understanding who is making journeys in grey fleet vehicles, and crucially, why, is an essential step when developing or improving a grey fleet policy. This involves analysing the available data and reviewing existing fleet policies.

In order to track progress, you’ll need to establish a baseline, using data from over 12 months to account for seasonal variations. It’s useful to collect data on mileages, payments claimed vs mileage rate, fuel use, number of claimants and non-car travel use. Data sources include telematics, booking systems, fuel cards and employee surveys.

Questions to consider include:


  • who are the drivers claiming grey fleet mileage?
  • are they fit and qualified to drive? What records are being kept?

Vehicles (grey fleet)

  • what vehicles are being used as grey fleet?
  • what are their carbon emissions?
  • are they fit for their purpose? (eg size, payload, age)
  • are they well-maintained, MOT certified, insured for business use? Do we have accurate records proving the above?


  • where are they going? (eg particular destinations)
  • why are they travelling?
  • how often are they travelling?
  • how far are they travelling? (ie average trip length)


  • what mileage rates are paid?
  • does the rate create an incentive to drive more miles?
  • what is the total mileage cost?
  • how do costs compare with fleet and daily rental vehicles?


  • who authorises travel?
  • who authorises mileage claims?
  • who has overall responsibility?

If this information is not available, you’ll need to review your data collection procedures.

To comply with health and safety legislation and the HSE’s Driving at work guidance, any grey fleet policy should include statements relating to the vehicle, the driver and the journey.

See Processes, drivers, considerations and monitoring for more details.

Appendix 2 in our guide to Managing and reducing grey fleet mileage lists measures that need consideration and monitoring.

You should also review current fleet policies. In particular, check that you know which employees are eligible for which type of vehicle and update the breakeven costs in terms of mileage and lease costs for company cars, pool cars and daily hire vehicles. It’s also worth reducing maximum carbon dioxide emissions allowed for company vehicles every year or so, because average carbon dioxide emissions improve year-on-year as new models become available.

Implement a travel hierarchy and travel plan

A travel hierarchy sets out a decision-making framework to minimise travel and its impact. The framework can take the form of a simple flow chart or an interactive website. Staff should follow the framework to help them make the right travel choice.

The first decision point should be whether a journey is required, or if phone or video conferencing would be suitable. See our guide to mileage management for best practice regarding web conferencing. The next step should be to consider public transport, walking or cycling.

Following this, the most appropriate vehicle is likely to be linked to mileage and may include daily hire cars, pool cars, car clubs, company cars or vans. Grey fleet should be the last resort.

To assist you in implementing changes, here are several example fleet policies to adapt:

Introduce or promote a company car scheme

Company cars may be the most cost-efficient option for employees undertaking high business mileage (ie over 8,000 or 12,000 miles a year). As company cars are normally newer, this also reduces emissions and leads to better risk management.

Where available, a lease car scheme can be cost-effective. An allowance is determined for employees towards leasing the vehicle, and business mileage is reimbursed (usually at HMRC’s advisory fuel rates) to cover fuel costs.

Salary sacrifice schemes are another option, but following taxation changes, they are now most cost-effective for ultra-low emission vehicles. This is where employees sacrifice a portion of their gross salary in exchange for a benefit – in this case, a company car. For more information, see the UK Government’s guidance.

It is possible to incentivise or require company car drivers to select lower emission choices, for example by restricting vehicle choice lists or setting a carbon dioxide cap. As company car tax and national insurance are closely linked to carbon dioxide emissions, this is also financially attractive for both employees and employers.

See the toolkit section on Choose efficient vehicles and Company cars: a guide for drivers and employers.

Replace grey fleet trips with pool cars or vans

A pool car or van fleet can be a simple, cost-effective, low emission and safe method of meeting staff travel needs, especially for daily trips.

To be effective, a pool car fleet needs to be well used by staff. Through the travel hierarchy, staff without company cars can be asked to use a pool car as their first option. It helps if there is a straightforward booking system and if vehicles are modern, comfortable and fit-for-purpose (i.e suitable for carrying equipment or clients if needed). Vehicles should be fuel-efficient and low carbon to maximise savings for the company. The target is to operate the pool car fleet at 45p/mile or lower, which is the grey fleet mileage reimbursement rate.

For help introducing or managing pool cars, take a look at our template Pool car strategy and adapt it to suit your organisation.

Also see Car share FAQs (covering pool cars, not car clubs) and the case studies below.

Replace grey fleet trips with daily hire

Hire cars are more cost-effective than a grey fleet vehicle for journeys over 80-100 miles a day. Using a daily hire vehicle also ensures the trip is made in a modern, well-maintained, lower emission car. It is possible to specify a carbon dioxide cap for the vehicles provided, such as 100g of CO2/km.

For further information, see Understand how daily rental can benefit your business. To help find the breakeven point, see Daily car rental vs private car costs spreadsheet.

Join a local car club

A car club provides its clients with quick and easy access to a car for short-term hire, to be used for local journeys.

Car clubs can be an alternative or supplement to pool cars, and can be very cost-effective where staff are making lots of short local trips. Your organisation may be able to host vehicles at your office or depot, or have exclusive use during working hours.

For an overview of the benefits, a comparison of car clubs to pool vehicles, and case studies, see our guide Learn how car clubs can improve your organisation’s efficiency.

Further information and advice can be found at CoMoUK (formally CarPlus).

Review mileage rates for grey fleet and company cars

Approved mileage allowance payments (AMAP) rates are set by HMRC, and are used to reimburse employees who have used their own vehicle for business travel, tax-free. They are designed to include the depreciation, fuel, insurance, servicing and maintenance costs. For the first 10,000 business miles, the AMAP rate is 45p/mile for cars and vans.

If an organisation pays staff more than the AMAP rate, this is considered a benefit, and employees will need to pay tax on the excess. We recommend that AMAP rates are used; if higher rates are used, there is an incentive to cover more miles.

We also strongly recommend that organisations use HMRC Advisory Fuel Rates (AFR) when reimbursing mileages for company car drivers. AFRs are around 11-14p for a typical petrol or diesel vehicle (see for current rates) and based on fuel costs. Using these rates discourages higher mileages, as it removes most ‘profit’ elements (except where large capacity efficient cars are in use) and discourages drivers from buying fuel at expensive locations.

Also consider using fuel cards for company car drivers and adjusting rates to reflect actual costs.

See Maximise fuel economy for details and methodologies.

Reduce the impact of grey fleet vehicles

Once alternatives have been provided and efforts made to reduce mileage where possible, the final stage is to reduce the impact of the journeys undertaken in grey fleet, to reduce emissions, and fulfil duty of care requirements.

Consider implementing minimum standards on grey fleet vehicles, especially cash ‘opt-out’ vehicles, giving good advance warning and a grace period. These should be based on the standards for company cars and include a maximum age limit of five years, for example, and include restrictions to ensure that appropriate vehicles are chosen by drivers.

An age limit for grey fleet vehicles (which are not cash ‘opt-out’ vehicles) could be set at seven years, a maximum mileage of 100,000 or 150,000 miles, or a carbon dioxide cap of 130g/km, or a minimum of NCAP 4-star crash rating.

If a clean air zone (CAZ) is being introduced locally, which will charge non-compliant cars and vans, a business could also set a minimum standard of a Euro 6 diesel or Euro 4 petrol vehicle. Businesses may also wish to update their expense policies to state that CAZ charges will not be covered if an employee chooses to drive a non-compliant vehicle.

Last updated: 18 November 2020