The incident in Ongar Road, in the area of Herons Lane, shortly before 8pm yesterday (Tuesday 10 August) involved a motorbike.
Sadly, the rider of the motorbike, a man, died at the scene.
His pillion passenger has been taken to hospital where her injuries are described as life-changing.
We are carrying out enquiries into the circumstances which led to the collision.
We need anyone in the area to check their CCTV, dash cam and doorbell cameras to see if they have caught any footage which may have captured either the incident or the moments before or after it.
The road was closed while we carried out enquiries at the scene but re-opened shortly before 5am.
If you have any information you can submit a report online at https://www.essex.police.uk or use the ‘Live Chat’ button to speak to an online operator between 7am-11pm.
Please quote incident 1189 of 11 August.
You can also call us on 101 or contact Crimestoppers anonymously on 0800 555 111.