Deanna Lim stood at a bus stop near Chinese Garden MRT station, sweat beading at her hairline. 

It was a weekday afternoon in May. The heat was unrelenting, Lim recalls. The 32-year-old financial consultant was due to meet a client in Tengah.

The bus was supposed to arrive in five minutes. It took 20 – and it did not arrive alone. A second bus of the same service was right behind it, nose to tail.

This is bus bunching, where two or more buses of the same service route arrive at a bus stop together, causing longer waiting times between bus arrivals.

“It was so frustrating,” recalls Lim, who was 15 minutes late for her appointment. “I don’t encounter (bus bunching) often, but when it happens, my schedule tends to get thrown off.” 

Lim mainly gets around with public transport. She explains that with back-to-back client meetings planned on most days, the delay meant her subsequent appointments risk getting pushed back too. 

Bus bunching is a common commuter frustration, acknowledges Tan Peng Kuan, managing director of SMRT Buses.

He explains that bus bunching happens when a bus falls behind schedule due to traffic, roadworks, or longer passenger boarding times.  

It is one of the areas that SMRT Buses aims to address through its Bus 4.0 transformation initiative, Tan, 57, says. (See box below)

Currently, an AI-powered system that detects bus bunching has been rolled out to across 20 bus service routes operated by SMRT Buses. 

The overall goal of Bus 4.0 is to deliver safer, smoother and more reliable bus journeys for commuters, says Tan.