The speed limit on Emirates Road and Sheikh Mohammed bin Zayed Road in Dubai is to be reduced.
Dubai Police and the Roads and Transport Authority said the limit was to be reduced from 120kph to 110kph to improve safety.
Speed cameras will be reset to trigger at 131kph, they said in a statement.
Emirates Road and Sheikh Mohammed bin Zayed Road are the most dangerous in Dubai.
Last year, 30 people died in accidents on the two motorways.
More to follow