The A43 is a primary route in the English Midlands and northern South East England, that runs from the M40 motorway near Ardley in Oxfordshire to Stamford in Lincolnshire. Through Northamptonshire it bypasses the towns of Northampton, Kettering and Corby which are the three principal destinations on the A43 route. The A43 also links to the M1 motorway. The section of the road between the M40 and M1 is designated a trunk road, managed and maintained by National Highways. The remainder of the route is the responsibility of local authorities. Route of road M40 to M1 The A43 starts at M40 junction 10 (the location of Cherwell Valley Services) which is widely regarded as being one of the worst motorway junctions in the country despite improvements made in the early 2000s. There are often long tailbacks at the junction, even at off-peak times. Following the junction with the M40, the A43 first meets a roundabout with the B4100 for traffic headed north-west for the village of Aynho or south for the town of Bicester. Continuing north, the A43 passes many Oxfordshire and Northamptonshire rural villages and towns before meeting the A421 which spurs towards Buckingham and later, Milton Keynes. The stretch of A43 through south Northamptonshire was upgraded to dual carriageway standard between the M1 and Towcester in 1991 and through to the M40 in the early 2000s. This was primarily to provide a link from the M1 to the M40 and also to Silverstone, home of the British Grand Prix. During the Grand Prix the A43 is closed to through traffic between Brackley and Towcester. The town of Brackley was bypassed in 1987. Just south of Brackley, drivers will approach a traffic island which spurs off in one direction for the A422 (for the M40 at Banbury and the A423 for motorists heading for Warwickshire) or the other direction which continues as the A43 into Northamptonshire. The A422 is met once again to the east of Brackley, allowing motorists an additional route into Buckinghamshire. Two miles north of Brackley, the B4525 (a B classified route for traffic from South Northamptonshire to reach the M40 at Banbury) joins the A43. From here, the A43 leaves the Oxfordshire borders and continues in a north-easterly direction towards Silverstone, where the road joins the A413 at a grade-separated junction. Later, the A43 bypasses Towcester, where it meets the A5 (Roman Watling Street) at