Drivers suffered severe traffic jams in northern cities on Wednesday due to the latest rail strikes.
Figures from location technology firm TomTom suggest the North was England’s worst-affected region for road congestion.
It was badly hit by the strikes as operator Northern suspended all services.
Manchester saw its congestion level hit 116% at 9am, up from 80% at the same time last week.
The level for Sheffield was 74% (up from 58%), while Liverpool’s figure was 75% (up from 60%).
Traffic elsewhere in Britain did not appeared to be particularly increased by the strikes.
In London, the congestion level rose from 76% to 79%.
But the level fell in Birmingham (from 70% to 69%), Bristol (from 78% to 69%) and Glasgow (from 65% to 53%).
This could be due to more people working from home.
The figures represent the proportion of additional time required for journeys compared with free-flow conditions.