Basement routing: How serving customers during F1 made us think outside the box

Grab Product Operations, Geo Tech teams

. October 5, 2025 . Regional

*This article was first published in October 2024. We’ve updated it to include new enhancements on basement routing in October 2025*

Singapore’s Formula 1 Grand Prix is a major attraction, drawing thousands of international travellers to the city-state each year.

It’s a challenging event for Grab. Road closures and limited access to pick-up points within the event zone impact our day-to-day operations. How well can we serve our customers and driver-partners under these circumstances?

We learn from F1 every year. Since the 2024 event, we’ve been working on solving a simple yet relevant challenge: How can we make it easier for our driver-partners to navigate through basements?

During F1, some pick-up points inside Singapore’s Central Business District (CBD) are only accessible through underground routes. But going underground can mean losing cell signal and GPS. This makes it difficult for driver-partners to find the correct pick-up location and also disrupts communication between passenger and driver.

(Also read: After the Singapore Coldplay shows, here’s how Grab “guides you home”)

The basement routing challenge

Here’s a concrete example. For the duration of the event, some hotels including the Ritz Carlton and Parkroyal are inaccessible through the regular entrance route. These hotels serve many travellers during F1, but the only way to reach them is via a complex web of interconnected basements.

Underground areas aren’t usually mapped in detail due to the lack of supporting data.

So, in preparation for the F1 2024 last year, we did just that. We digitised the underground routes on GrabMaps. We had to take into consideration that there are multiple levels, and that the newly mapped data is in accordance with the guidelines of Open Street Map—the open source map GrabMaps is based on. This required collecting field data at the location to plot route references, and enhancing them with the help of a mapping app which is designed to work offline.

Leading up to the event last year, we also enhanced our in-app communication with drivers-partners and passengers.

For example, if a route to a passenger’s pick up location took a driver-partner through one of these basements, they’d see a pop-up message starting 100 metres before the underground route begins.

This pop-up serves as a reminder for drivers and helps them capture a mental image of the underground route, as they’re expected to lose their cell signal soon, and with that, their real-time positioning.

The improved experience in 2025

In 2025, we’re going one step further, enabling driver-partners and passengers an even smoother experience throughout the event.

We have now enabled indoor navigation for the basements, which allows drivers to understand their position relative to the map even without GPS signal.

This is possible due to the introduction of dead reckoning (DR) and magnetic positioning technology. DR relies on motion sensors, such as gyroscopes and accelerometers found in smartphones, and estimates the current position based on previous known location.

Magnetic Field Matching (MFM) uses Earth’s magnetic field waveforms for localisation. Combined, these two technologies can estimate a real-time position for vehicles navigating through indoor locations without relying on GPS.

Clear audio-visual guides and communication

We’re also upgrading guidance for driver-partners throughout their journey. They’ll see an image of the basement entrance on their navigation screen as they approach, and the voice guidance will also give them a reminder.

Since we started implementing solutions for basement routing, we’ve measured positive impacts.

During F1 2025—compared with figures from last year’s event—we observed an improvement in fulfilment rates specific to pick-ups that required basement route access. This means, more passengers and drivers had a smooth booking experience and completed their trips successfully.

We also measured reduced contact rates, which is the number of times drivers and passengers needed to message each other prior to pick-up. High contact rates indicate friction, such as difficulty of finding each other.

In 2025, we had a lower contact rate for both messages and calls compared to 2024, indicating there was less pickup point confusion.

Large events push us to do better

Basement navigation is just one of many challenges posed by mega-events like F1. We’ve also been working on other improvements, like a more immersive way to guide passengers to the right pick-up locations within the F1 zone.

Major events like the Grand Prix are an opportunity for our teams to stretch the limits and solve novel, real-world problems. Solutions developed for special occasions help us innovate and improve the overall platform experience.

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