Pont Mathilde Closure Rouen
If you are travelling from Calais be aware that the main bridge crossing the river Seine in Rouen is currently closed due to a fire as a result of a Petrol Tanker crash, it is supposedly re-opening some time in the Summer of 2014.
In the meantime you will need to take a detour.
Heading from Abbeville towards Rouen
Travelling South from Abbeville you will pass the Aire Maucomble Services which has a petrol station and a shop. You then drop down into a valley and rise up the other side. At the top of the hill you need to take the turn off to the right at Junction 11 heading for Le Harve and Fecamp - you then follow the directions as per document below - there will be diversion signs - Le Mans, Alencon, Caen and Le Harve are the direction you want to be headed. If you have SatNav it should compliment the directions provided here.
Heading from South West of Rouen
On your return you need to be really on the ball as there is just one sign, easily missed, alerting motorists to the diversion. Returning you will presumably have travelled up the Autoroute from Le Mans. When you clear the tolls head East for Rouen on the E402, there are services on this road at Aire Bosqouet soon after you join it from clearing the A28 tolls. You need to turn off the E402 for the diversion at Junction 23 which is signposted for Rouen Centre, there is a single sign warning that there is a diversion due to bridge closure but it is not obvious or prominent.
Stay on the dual carriageway as you plunge down towards Rouen Centre - again there are no diversion signs. You will eventually see a sign saying Sotteville and St Sever with an arrow pointing bottom right with a height limit (underpass) - at this point you want to be in the middle or Right hand lane as you need to turn left at the upcoming roundabout rather than go through the underpass. As you approach the roundabout you want to be in the left hand lane as you need to be turning left following signs for the A150 Dieppe - the next bit after the roundabout is a bit twisty but you want to be heading for Dieppe and crossing the Seine. You then climb up out of the valley and hopefully there will be diversion signs, but in essence you are heading North-West whereas you want to eventually be heading North-East - from memory there are diversion signs that will take you back to the main autoroute from Rouen to Abbeville. The document below clearly identifies the route and road numbers.