The Citymapper Mobility Index shows trip activity compared to a normal baseline – Singapore was late to cut its transit ridership compared with Hong Kong and Seoul (source: CMI)

Hong Kong mobility plunged faster and further than Singapore’s during the Covid-19 crisis, according to the Citymapper Mobility Index (CMI), which tracks the number of trips planned by people using the Citymapper app and compares against “typical” usage (2-22 December in Hong Kong and Singapore).

The app, which tracks all trips except driving, shows Hong Kong mobility down to an average of 37% for the last 28 days, against 51% for Singapore. On 2 March, Hong Kong’s ridership was half of normal, while Singapore was at 88% of its baseline, a level that didn’t start to fall significantly until mid-March. Only in the last six days have Singapore’s numbers sunk below Hong Kong, with Singapore ridership dropping off a cliff to just 21% of normal on 7 April, against 36% in Hong Kong for the same day. Singapore’s “new low” is maintained until today, with just 16% of baseline travel, according to the CMI.

Covid-19-watchers are keenly analysing differences between Hong Kong and Singapore as the two cities have experienced a rapid divergence in virus cases. While Hong Kong’s “second wave” is petering out from a peak of 82 new cases on 29 March, Singapore is now seeing a rapid rise, with 619 new cases reported on Saturday and Sunday (against nine in Hong Kong on the same weekend) and triple-digit new cases for every day in the last week.

Citymapper says its users are public transport users, and also people who walk, cycle and use scooters and cabs. While the CMI is limited to measuring changes in behaviour from those who regularly use its app, the firm says its methods are sound. “We have enough data in our published cities to be confident that it represents a real change in behaviour,” says the firm.

Besides, other digital firms are finding similar trends: Google’s new COVID-19 Community Mobility Reports, which use Google’s smartphone tracking “Location Services” to watch visits to key places within a city, reports Hong Kong grocery visits down 16%, against just down 1% for Singapore, since the end of February. Hong Kong transit hub use, according to Google, is down 47% against 40% for Singapore, while park use is down 50% in Hong Kong against 27% in Singapore.

Google’s COVID-19 Community Mobility Reports show Singapore has barely stopped shopping, while Hong Kong grocery store visits are down 16%

Official numbers for Hong Kong’s MTR and other public transport are not available for comparison with the digital market: the latest data from MTR is February, which showed 71 million trips for the month against 126 million a year ago, down 44% on 2019. Meanwhile Transport Department data for January shows a 15.7% drop in average public transport patronage, a 7.7% drop in vehicles using Cross Harbour Tunnels and a rise in the use of licensed vehicles by 0.8% compared with January 2019.