A serious crash has left an 18-year-old driver dead and caused traffic chaos when part of the Mitchell Freeway was closed for at least five hours.

A white Nissan Patrol was travelling northbound when the teenage driver lost control near the Powis Street exit, and rolled.

He was the only person in the car, and was taken to Royal Perth Hospital but died a short time later.

Police blocked the northbound lanes of the freeway from Vincent Street to Hutton Street, with motorists being forced to exit the freeway as congestion built as a major crash investigation was launched.

It was the second fatal crash in 24 hours, after a crash between a motorcycle and a ute on Tonkin Highway on Saturday.

The female motorcyclist, aged 61, died in hospital on Saturday night.

Major crash officers are investigating both crashes and are appealing for anyone who witnessed them to report to Crime Stoppers via www.crimestopperswa.com.au or by calling 1800 333 000.

Dash-cam or mobile phone vision relating to the crash can be uploaded directly to investigators via the following link, https://wapf.au.evidence.com/axon/community-request/public/glendalough