Signs have gone up on the Cookstown to Moneymore dual carriageway alerting motorists to the new lower speed limit.
It’s been reduced from 70 to 60mph.
The carriageway has been the scene of many fatalities over the years.
There have been attempts to get the speed limit lowered several times.
Woman in critical condition after she's struck by car in Belfast
Man dies following road accident in County Fermanagh
Executive will ‘have to deal’ with compensation costs from PSNI data breach
Man remanded in custody charged in connection with mosque burning plot
Woman charged over breaches at abortion safe access zone