|North Orbital Road|
|From:||Leavesden Green (TQ097997)|
|To:||Park Street (TL143050)|
|Length:||4.8 miles (7.7 km)|
|Meets:||A41, A412, M1, M25, B4630, A414, A5183|
|Old route now:||A412, M25, A414|
|Route outline (key)|
Starting at a grade-separated roundabout junction on the A41 Watford bypass, the A405 heads north-east then north to bypass Abbots Langley. Although the road is D2 speed is limited to 40 mph owing to the large number of side roads and occasional roundabouts. The limit increases to 50 mph before we reach the M1 at the Waterdale Interchange (Junction 6).
Now carrying traffic between central London via the M1 and the M25, the road passes to the west of Bricket Wood and soon reaches a roundabout at J21A of the M25. On the far side of the motorway – and still D2 – the road bears right at the next roundabout to bypass Chiswell Green and presently we reach Park Street Roundabout to the south of St Albans where we meet the former A5 (now A5183) and former M10 (now A414). The road ends here.
The A405 was originally planned to be part of an orbital road encircling all of London.
When first built in the 1930s it ran from the A41 in Watford to the A555 (now A1) Barnet bypass, passing to the south of St Albans. By the 1970s the road had been extended west to bypass Rickmansworth and met the A412 at Maple Cross.
The Rickmansworth bypass was later upgraded and incorporated into the M25 as the section between J17 and the spur at J19 (although the spur at J17 is now the A412). Later still, the St Albans bypass was incorporated into a rerouted A414, giving the road its current length.