A main Croxley Green road will be closed today so the carriageway can be resurfaced.
Baldwins Lane will be shut from the junction of The Green to the junction of Watford Road from 9.30am to 3.30pm.
The work begins today and is due to be completed on Wednesday.
A diversion route is in place along The Green and Watford Road.
Eurovia will be carrying out the work on behalf of Hertfordshire County Council.