A23 between Bolney and Crawley closes overnight
A key route through West Sussex is to be completely closed overnight six nights a week for the next three weeks.
The A23 between Bolney and Crawley will be shut both ways from 20:00 to 06:00 GMT every night excluding Fridays.
It is to allow tree felling in preparation for major road works next year as part of the A23 Handcross to Warninglid road-widening scheme.
The Highways Agency said the work should be completed by 27 November, weather permitting.
It added the closures would take place when traffic flows were at their lowest, but these would be monitored and start times could be changed accordingly.
Diversions will be in place with access to local villages maintained.
The new road scheme, which is scheduled to open in autumn 2015, aims to reduce congestion on the main route between London and Brighton.