I had queried the flow assessment. I was told The Design Year for traffic flow assessment is set for 2031. That's only 15 years after the planned opening of the A5-M1 Link, which at the moment is expected to be in 2016, according to the Secretary of State's Preferred Route Announcement.
I wondered if all the planned new builds had been factored in? They're saying that the modelling work for the A5-M1 Link (Dunstable Northern Bypass) takes into account traffic generated by approximately 17,000 houses and commercial activities as advised by the Planning Authority. These developments are located just north of Houghton Regis. The model assumes that the remaining houses identified in the MKSM sub-regional strategy will be allocated in other areas. It also assumes that the new housing development will have its own spine road to handle traffic within the development. Only longer-distance trips would make their way onto the external highway network.
They clarified that the plans for the A5-M1 Link call for an All-Purpose Dual carriageway.
Remember that incident on April 18, 2007, when the M1 was closed in both directions between Junctions 13 and 14? Yeah, that was a mess. DFT says it knows and has documented the impacts of that incident. I wondered if this new road would cater for this kind of disaster. Now, here's the thing: they admit that designing a road network that can handle such exceptional events wouldn't be economically feasible. Typically, they provide capacity for average traffic flows, not these super-exceptional ones like what happened that day. So, when events like that occur, severe congestion is pretty much inevitable. The new A5-M1 Link would have helped ease the situation by providing an alternative access route to the M1 southbound for diverted traffic. That way, it could have avoided passing through Dunstable/Houghton Regis to reach Junctions 11 or 9. Northbound traffic could also have used the Link to divert via the A5. But hey, even with signed diversions, drivers are entitled to use whichever public highway they fancy, as long as their vehicles are legal and they follow the regulations. So, they might choose a different route they think will be better.
They're saying the traffic model takes into account the road conditions in Houghton Regis and on Poynters Road/Park Road North. If the A5-M1 Link is built, it would remove the through movements on this route, especially the east-west ones. However, we expect that local trips would take advantage of this relief, which means flows in Houghton Regis High Street could fill up again.
In four years time, 2011, the forecasted flow for the A5120 is 13,300 vehicles per day. This forecast assumes that the M1 will be widened to four lanes, but without an A5-M1 Link (Dunstable Northern Bypass) and without any new housing development to the north of Dunstable. If the A5-M1 Link were to be provided, the forecasted flow would decrease to 7,700 vehicles per day.
Looking ahead to the year 2026, the forecasted flow for the A5120 is 24,700 vehicles per day. This forecast considers the M1 being widened to four lanes but without an A5-M1 Link (Dunstable Northern Bypass). It also includes 17,000 new houses to the north of Dunstable, along with a spine road through that housing area. If the A5-M1 Link were to be built, the forecasted flow would decrease to 14,200 vehicles per day.
The A5-M1 Link (Dunstable Northern Bypass) is designed to replace the Dunstable Eastern Bypass. Its aim is to divert traffic heading to junctions 11 and 12 away from the local road network in Dunstable, Houghton Regis, and the surrounding villages. By the way, there have been some informal discussions about detrunking the A5 after the A5-M1 Link opens.
The specific form and design of the junctions in Houghton Regis are under the jurisdiction of the local highway authority. They're the ones responsible for making those decisions.
So, there you have it. A few replies from DFT.
