Parts of Reading remain at a standstill along diversions put in place during a planned closure of the M4.
The major route has been closed westbound since 9pm on Friday between Junctions 11 and 12 so that National Highways can carry out essential works, related to introduction of the smart motorway.
On Sunday, traffic service TomTom was reporting delays of around two hours on diversion routes, with Reading buses saying all their services are affected.
Many people have taken to social media describing being stuck in traffic for several hours, with some complaining the closure were not sufficiently publicised.
The M4 is due to reopen fully at 6am on Monday.