But after waiting until 7.20am, he hastened across the road to a taxi stand for a 56-minute ride, which cost $75.20.
He complained to Auckland Transport, which replied that the Ritchies Transport bus he was due to catch was running 22 minutes late for a reason unknown to it.
"We regret the inconvenience caused and trust that in future our service will provide the kind of travel experience that meets your expectation," a customer service representative said in a response letter.
"We appreciate that delays and cancellations are frustrating and inconvenient, and we are striving to minimise them," she said.
"Should the irregular running of this trip prove to be repetitive, we will request that our scheduling team review the possibility of changes to the Ritchies 081 service to improve performance in the future."
But Mr Dai said the council transport body should back up its words and refund him the taxi fare.
"It's really unfair. Where to find justice?" he asked the Herald.
Ritchies Transport operations manager Belinda Ritchie said the bus started its run on time at Westgate but was held up in Universal Drive by "absolutely diabolical" traffic.
"It was at an absolute standstill," she said, of traffic backed up from the Lincoln Rd ramp to the Northwestern Motorway.
"They're doing major roadworks on the motorway, so you've got so much back traffic -- some days are really good, other days are absolutely diabolical."
Although the reconstruction of the Lincoln Rd motorway interchange has been completed, work is continuing further east at the Te Atatu interchange and on Te Atatu Rd, where Auckland Transport has closed one lane while widening it.
Its spokesman said it had checked travelling times of 20 buses on Ritchies 081 service for 12 days from November 23 and found just two were more than five minutes late starting their runs.
"However, there appears to be an issue on Universal Drive, where on one occasion it took a bus 13 minutes to travel 700 metres," he said.
"The average time for this stretch is five minutes.
"There are extensive roadworks in West Auckland at the moment, and at times that may affect bus services as well as driving times for all motorists."
But although officials would keep monitoring the 081 service "to see if we need to consider measures such as bus priority [lanes]," the spokesman ruled out any compensation for Mr Dai.
Although replacement taxis are sometimes provided for stranded train passengers, he said that equated to maintaining a transport service and no fares were reimbursed.
