The road is closed northbound between the Carholme and Riseholme roundabouts. Motorists have been urged to find an alternative route while the incident is dealt with.
It is not yet known how long the road closure will be in place for. Police are at the scene. A spokesperson for the force said: “We have been alerted to a broken down vehicle on the northbound carriageway on the A46.
“The road has been closed between the Carholme and Riseholme roundabouts. We are asking people to avoid the area and to seek alternative routes where possible.”
Follow our live blog below for regular updates.