UK car dealers, caravan retailers, and motorhome businesses now have two powerful automotive inventory advertising platforms: Google Vehicle Ads and Meta Automotive Inventory Ads. This guide explains the practical differences — not the marketing speak, but the actual feed requirements, strengths, and trade-offs.

The fundamental difference in buyer intent

Before getting into feeds and formats, it's worth establishing the strategic difference between the two platforms.

Google Vehicle Ads reaches buyers who are actively searching. When someone types "used Bailey Alicanto caravan" or "Ford Transit Custom under £25000" into Google, they're in research or buying mode. The intent signal is explicit. Google Vehicle Ads capture this intent and match it to your specific inventory.

Meta Automotive Inventory Ads reaches buyers who have shown relevant interest. They might have visited your website, looked at a specific vehicle, or engaged with automotive content on Facebook or Instagram. Meta's algorithm uses these signals to serve them highly personalised inventory ads — but the intent is inferred, not stated.

Both are powerful. They serve different stages of the buyer journey and should be run simultaneously for best results.

Feed format comparison

Google Vehicle Ads uses an XML feed submitted to Google Merchant Center. The XML uses the standard Google Shopping RSS namespace with vehicle-specific attributes. Required fields include: id, title, description, link, image_link, price, availability, make, model, year, condition, and store_code.

Meta Automotive Inventory Ads uses a CSV file uploaded to Meta Commerce Manager with a Vehicles catalogue type (not the standard Products type — a critical distinction). Required fields include: vehicle_id, make, model, year, mileage.value, mileage.unit, body_style, state_of_vehicle, price, exterior_color, url, image[0].url, availability, vin, and condition.

The underlying data is the same — make, model, year, price, images — but the format, field names, and delivery method are completely different. You cannot submit a Google Vehicle Ads XML to Meta, or a Meta CSV to Google Merchant Center.

UK-specific differences

Both platforms have UK-specific handling:

VIN handling: In the UK, VIN (Vehicle Identification Number) is classified as Personally Identifiable Information (PII) under UK GDPR. For Google Vehicle Ads, VIN is entirely optional — use your internal stock ID as the identifier instead. For Meta, VIN appears as required in the spec but UK dealers typically use an internal reference number. Both Trajekt and Meta's support documentation acknowledge this UK exception.

Mileage units: UK vehicles use miles. For Meta, set mileage.unit to "MI" (not "KM"). For Google, specify your mileage in miles. This seems obvious but automated feed tools often default to kilometres.

Price formatting: Both platforms expect VAT-inclusive prices — what the consumer sees on your website. Don't submit ex-VAT prices.

Vehicle types supported

Both platforms support all vehicle types:

  • Cars and SUVs
  • Vans and commercial vehicles
  • Caravans and motorhomes
  • Campervans
  • Motorcycles

This is particularly relevant for UK recreational vehicle dealers — both Google and Meta support caravan and motorhome inventory. Trajekt has been specifically tested with UK caravan and motorhome dealer data from Bailey, Coachman, Swift, and other major brands.

Images: where the biggest difference lies

Both platforms benefit significantly from multiple high-quality vehicle images. But they handle them differently:

Google Vehicle Ads accepts up to 10 additional images via additional_image_link. Exterior front three-quarter view is the primary image; additional images can include side profiles, interiors, and detail shots.

Meta AIA uses a structured image array: image[0].url through image[2].url as standard fields (more can be added). Meta uses these images to generate dynamic ad creative across different formats — carousel, stories, collection ads.

In both cases: exterior shots on clean backgrounds, no promotional overlays, real photos of the actual vehicle (not stock imagery), minimum 1000×750px.

Costs and measurement

Google Vehicle Ads operate as Google Ads campaigns — CPC model, you set bids per vehicle group. Performance is measured in Merchant Center (impressions, clicks) and Google Ads (conversions from your tracking).

Meta AIA operates within Meta Ads Manager — CPM and optimised CPC models, audience-based targeting. Meta Pixel tracks website actions (vehicle page views, enquiry form completions) that can be attributed to Meta ads.

Industry data suggests Google Vehicle Ads typically deliver higher-quality leads (stronger purchase intent) while Meta AIA delivers higher volume at lower cost per click. Running both and comparing cost per enquiry over 90 days will tell you the right budget split for your specific dealership and inventory type.

Run both from one inventory source

Trajekt connects to your vehicle inventory once and generates both Google Vehicle Ads XML and Meta AIA CSV — with UK VIN handling and twice-daily updates.

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Which to prioritise first?

If you're starting from scratch: start with Google Vehicle Ads. The intent signal is stronger, the setup is more straightforward (if you already have a Google Merchant Center account), and the path from click to enquiry is shorter.

Once Google Vehicle Ads is running, add Meta AIA within the first 3 months. This lets you retarget Google-driven website visitors on Meta — capturing buyers who visited your site from Google ads but didn't enquire.

Running both typically delivers 30-45% more enquiries than either platform alone, at a combined cost lower than running Google at 1.5× budget.