Managing your Grey Fleet with ABAX

Grey fleet is one of the biggest blind spots in business transportation. With 14 million privately owned vehicles used for work, grey fleet makes up 40% of all cars on UK roads. Yet, many businesses lack visibility into its costs, compliance risks, and environmental impact. As sustainability reporting and fleet efficiency become top priorities, companies must take control of their grey fleet strategy.

"Grey fleet vehicles often contribute significantly to a company’s carbon footprint, particularly if they consist of older, less fuel-efficient cars. Without accurate reporting, businesses may be underestimating their environmental impact," says Niall Curran, Senior Business Development Manager at 5Y Technology.

The grey fleet challenge: what’s at stake?

1. Compliance risks: is your business exposed to penalties?

Grey fleet drivers use personal vehicles for business travel, but without a structured approach, businesses could be failing in their duty of care and tax compliance responsibilities. According to Fleet News, organisations that do not track grey fleet mileage correctly risk fines of up to £34,000 per vehicle from HMRC. Misreporting business and private mileage is a common issue, and manual tracking methods increase the likelihood of errors.

"Ensuring compliance with sustainability regulations is just as important as tax reporting. Many businesses are facing increasing requirements to disclose emissions from all business travel, including grey fleet," adds Niall Curran.

2. The hidden costs of grey fleet

At first glance, grey fleet seems cost-effective—businesses avoid upfront vehicle costs and maintenance expenses. However, the financial benefits diminish as travel needs increase. Fleet News reports that unchecked mileage reimbursements, fuel inefficiencies, and vehicle wear-and-tear contribute to rising costs.

A well-managed grey fleet policy should include mileage tracking, cost analysis, and alternative transport options for frequent travellers. Without proper oversight, businesses may be overpaying on reimbursements or missing opportunities for cost savings.

3. The environmental impact of an ageing fleet

A study by the British Vehicle Rental and Leasing Association (BVRLA) found that the average grey fleet car emits 19% more CO₂ than a company-owned vehicle. Older, less fuel-efficient vehicles make up a large proportion of grey fleet, significantly increasing an organisation’s carbon footprint.

At 5Y Technology, ABAX mileage data is used to streamline fleet emissions reporting. "We have successfully accessed journey distance data from ABAX. Utilising ABAX APIs, we can calculate emissions for each journey across a company’s entire fleet, including grey fleet, eliminating this time-consuming task for sustainability teams," explains Niall.

4. Safety and risk management

The lack of control over grey fleet means that businesses have no oversight on driver behaviour, vehicle condition, or safety risks. According to a report by Marsh, grey fleet vehicles contribute to higher accident rates due to inconsistent maintenance, lack of vehicle safety monitoring, and driver fatigue. Businesses that fail to implement risk management strategies may face increased insurance costs and potential liability.

Unlocking grey fleet potential with ABAX

Managing grey fleet doesn’t have to be a logistical nightmare. With the right technology, businesses can regain control, reduce costs, and meet sustainability goals. 

ABAX Triplog provides:

• Automated mileage tracking – Ensuring accurate HMRC compliance and removing manual admin.

• Cost optimisation – Identifying unnecessary mileage and improving reimbursement accuracy.

• Sustainability reporting – Integrating data with platforms like 5Y Technology to measure and reduce emissions.

• Privacy-first tracking – Allowing employees to separate business and personal trips with built-in privacy controls.

"The ability to integrate ABAX mileage data with sustainability platforms like ours means businesses can track and reduce their grey fleet emissions with ease," says Niall.

Upgrading from ABAX Triplog to ABAX Fleet

While ABAX Triplog is a powerful tool for tracking mileage and ensuring compliance, businesses that manage a combination of grey fleet, company-owned vehicles, and assets can unlock additional benefits by upgrading to ABAX Fleet.

Key benefits of ABAX Fleet:

• Full visibility across all vehicle types – Manage grey fleet, company-owned vehicles, and leased assets in one system.

• Real-time vehicle tracking – See where vehicles are at all times, improving response times and fleet efficiency.

• Driver behaviour monitoring – Identify harsh braking, rapid acceleration, and excessive idling to reduce fuel costs and enhance safety.

• Fuel efficiency tracking – Gain insights into fuel consumption and reduce unnecessary fuel spend.

• Predictive maintenance alerts – Reduce vehicle downtime and prevent costly breakdowns with proactive servicing reminders.

Taking control of the invisible fleet

Grey fleet is a growing influence in business mobility, yet many organisations remain unaware of its financial and environmental impact. With ABAX’s advanced tracking and integration capabilities, businesses can take full control of their grey fleet—improving compliance, cutting costs, and driving sustainability.

📍 For businesses looking to go beyond mileage tracking and optimise their entire fleet operation, ABAX Fleet offers a complete, future-proof solution.

📍 Visit ABAX at the Great British Fleet Event to discover how we can help your business turn grey fleet challenges into opportunities.