Sydney's new Metro Northwest has made Nathan Burke's daily commute longer by three minutes, but he doesn't mind.

The ABC followed Mr Burke, a father-of-two from Kellyville Ridge, on two separate journeys to his North Sydney office.

Before today Mr Burke had only one option — the road.

But that all changed on Sunday, when Sydney's new driverless Metro Northwest opened.

On Friday, the trip to North Sydney on some of Sydney's busiest arteries — the M7, M2 and Lane Cove Tunnel — took one hour and seven minutes.

He said that was a pretty good run.

"It's usually about 10 minutes worse than that," Mr Burke said.

He hoped the Metro service would allow him to leave later.

"I'm just hoping to spend more time with the kids, and not rush out the door," he said.

"Get a little bit more sleep [and] obviously get home a little bit earlier as well."

Metro Northwest, Australia's first driverless passenger train, went through its first peak-hour test this morning.

About 21,000 people used it between 4:00am and 10:00am — about 80 per cent of them had to transfer to another form of public transport.

Mr Burke drove from his home to Kellyville Station and parked in one of the 4,000 new car parks scattered along the line.

After waiting at the platform for three minutes, he got on to a largely empty carriage, which filled up when it arrived at Epping.

About 8,000 passengers used that station this morning between 4:00am and 10:00am while Macquarie University (6,000) and Chatswood (9,500) were also busy.

Metro Northwest terminates at Chatswood, and the platform was crowded, but no more so than what it usually would be during Sydney's morning rush.

The route Nathan took to work today. ( ABC )

After changing to an over-ground train at Chatswood, Mr Burke began the final leg of his journey to North Sydney.

It took three minutes longer than the drive, but he's not complaining.

"It's pretty good considering how long it [driving] can normally take," he said.

There were no delays during Mr Burke's commute.

"It's marginally slower than the car, but in terms of how much the cost is when you consider tolls, and fuel, it's probably about $100 a week better off," he said.

"It was a very comfortable ride, and everyone knows how stressful traffic can be, so I'll take that any day."

Passengers were overwhelmingly positive about their experience on the Metro.

"It's a really good contribution to our community. It's cut down my travel by an hour," one woman said.

Another passenger told the ABC his journey time had been slashed.

"It's saving about an hour each way, which is very good," he said.

"It gives me more time with my family which is very important."