Is your grey fleet growing? Processes, tools and systems to stay on top 

If employees in your organisation use their own cars for work, you’re already managing a grey fleet — whether you’ve formalised it or not.

That comes with processes for tracking mileage, handling compliance, and collecting and approving claims. As your organisation grows, you need a few guardrails in place to prevent admin creeping up, visibility from slipping, and compliance becoming harder to stay on top of.

Here’s how to stay in control as you grow:

• At ~10 drivers: Put basic guardrails in place — consistent mileage reporting, clear ownership, and simple checks
• At ~25 drivers: Standardise and streamline — manual approvals, document chasing, and fragmented processes start to slow you down
• At 50+ drivers: Build for scale — clear ownership, audit trails, and systems that keep everything consistent across teams

What changes as your grey fleet grows

A growing grey fleet usually becomes harder to manage in three ways:

The trigger is usually that manual processes don't hold up when the organisation grows. The fix is putting the right checks and systems in place before admin, reimbursement errors, and compliance gaps pile up.

Our research with teams managing employee mileage shows a clear pattern:

“As teams grow, informal mileage processes break down — not due to bad intent, but because checks and oversight don’t scale.”

- Source: Sales & Onboarding Call Analysis, 2025

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Before you scale, check whether a grey fleet is still the right model for your business 

A grey fleet is the right setup for many Australian employers — especially when employees drive occasionally, or when business travel spans office, field, and hybrid roles.

But it’s worth reviewing when:

• Annual business kilometres per driver start climbing
• Drivers travel regularly between multiple sites
• The business needs tighter operational control

If you’re weighing up whether personal vehicles still make sense, see our company car vs personal car guide.

At 10 drivers: replace ad hoc processes

Under 10 drivers, a grey fleet is typically in what you might call the reactive stage: ad hoc mileage tracking, no formal written policy, and compliance handled manually. Mileage claims arrive in different formats, approvals depend on who submitted what, and key checks often live in someone’s memory rather than a system.
This is the “hero” stage, where one person takes charge simply because someone has to. It works at small scale. It doesn’t scale.

What to put in place

• One consistent method for logging and submitting mileage
• A named owner for licence, insurance, and registration checks
• A simple reimbursement process 
• A written policy explaining what counts as business mileage
• If you’re unsure about where your current setup stands, start with our grey fleet risk assessment guide — it sets out what employers are expected to manage and how to document it.

Under WHS law, that expectation applies to employees using their own vehicles for work, not just company-owned cars.

If you need a policy baseline, start with a grey fleet policy template.

At 25 drivers: admin becomes the bottleneck

Around 25 drivers: a grey fleet enters the controlled stage. Ownership, documentation, and automation become critical.

If you're still managing mileage manually, costs due to admin time and inaccurate mileage claims, can start to drift. Small inaccuracies — rounded distances, missed or duplicated trips — add up across dozens of drivers. No one is acting in bad faith, but mileage inflation becomes almost inevitable without properly recorded trips.

By the time a grey fleet reaches 25 drivers, mileage administration needs to be automated — from tracking through to approval.

Our research with new team administrators reflects the same pattern:

“Reviewing mileage reports is consistently described by administrators as the most time-consuming part of the process, largely due to manual verification and missing or inconsistent data.”

- Source: Sales & Onboarding Call Analysis, 2025

Driver documents often sit across shared inboxes, folders, and spreadsheets. Different managers check mileage and compliance in slightly different ways. Claims get approved without consistent controls to flag anomalies.

As accountability blurs, risk increases.

Weak mileage records don’t just create administrative friction; they can lead to tax and audit issues. If you reimburse employee mileage, records must be accurate, complete, and consistent enough to meet ATO record-keeping requirements, including retaining evidence for 5 years and linking claims to actual business travel.

What to scale at this stage

• Automate mileage capture where possible. This removes estimates, missed trips, and duplicate entries.
• Standardise approval flows. Managers should review claims the same way, using the same evidence.
• Schedule recurring document checks. A practical baseline is annual verification of licence, business-use insurance, and current registration (plus any state-based roadworthy or safety check that applies).
• Document who does what. If finance approves payment, managers verify journeys, and HR or operations handles eligibility — write that down.

At 50+ drivers: structure becomes non-negotiable

At 50+ drivers, a grey fleet enters the optimised stage: compliance has to be built into the system, not bolted on after the fact.

You’re no longer managing a single group of drivers. You’re most likely managing multiple teams within one organisation, each with its own managers, approval flows, and reporting needs.

Your setup has to support both team-level independence and central control. Without it, simple questions get hard to answer:

• Are all drivers currently insured for business use?
• Are checks being completed on time across teams?
• Can you produce a clear mileage record if the ATO asks?
• Is responsibility for oversight actually defined?

At this size, informal oversight fails because the process depends on local habits rather than central controls.

As one operations manager we spoke to during our research explained:

“When you look at the expenses, people are just putting ‘I drove 200 km’. But nobody really drives exactly 200 km — it might be 198 or 203. At that point, you realise people are just estimating.”

- Source: Sales & Onboarding Call Analysis, 2025

What good looks like at 50+ drivers

At this scale, privacy is part of the compliance conversation — but it’s also an adoption question.

Employees are driving their personal vehicles, often on their personal time, and location history is sensitive personal information.

A privacy-first tracking design isn’t just a legal fit; it’s the practical way to ensure tracking is used consistently across a growing team.

The checklist: signs your grey fleet process is no longer scaling

Use this as a quick self-check. Your process likely needs attention if:

• Mileage reports come in multiple formats
• Managers approve claims differently across teams
• Employees round journeys or estimate distances
• Licence, insurance, or registration checks rely on reminders
• Records sit across inboxes, spreadsheets, and shared folders
• Nobody clearly owns the end-to-end process

If several of those apply, the issue isn’t the size of the grey fleet alone. It’s that the process has outgrown the controls around it.

The next step

A grey fleet doesn’t suddenly become unmanageable at a fixed number of drivers. What fails is a process that never evolved beyond trust, spreadsheets, and manual checks.

If your team is growing, the safest move is to add structure early — before approvals slow down, records become patchy, and compliance becomes harder to prove.

Review your current setup against each growth stage above.

If you need the wider framework, start with the complete grey fleet guide or compare your vehicle options in the company car vs personal car article.

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