Tuesday, February 21, 2012

The crossings for Tesco

My questions have been answered even the ones I didn't ask - how do pedestrians gain access to Tesco; and how is the traffic from Severn Road supposed to exit onto the near blind corner of Mitton Street?

The answer is simple, but not one you'd discover from the plans submitted. As detailed on the site plan internally labelled as 6046-P10 a splitter triangle is to be placed at the mouth of Severn Road; again as shown two "pedestrian link[s]" will be added across the mouth joining the splitter. What isn't shown is that an additional pedestrian link will be placed across Mitton Street to connect to the splitter.

Both this and the Severn Road links will be a set of "phased traffic lights" or to put it in layman's terms - a normal set of traffic lights that alternate between red and green though apparently they'll be set and "tweaked" to only switch when there is actual need. What does this mean? It means traffic rounding the corner of Mitton Street and being confronted by a set of lights; it potentially means traffic in the left hand land being blocked be traffic being halted at the mouth of Severn Road. As a consequence traffic will stick to the right-hand lane until they know the left is clear.

Due to this traffic coming down the Worcester Road towards the island and subsequently into Mitton Street will instead head down Discovery Road and into Severn Road because they know even more traffic wants to enter the right hand lane of Mitton Street so that junction will be treated as a priority more so than it is currently and thus become blocked up; while at the same time it offers the certainty of being able to enter Mitton Street unhindered from Severn Road rather than hoping to be able to get out at the island. In other words they've created a rat-run.

It gets better - I've never seen any plans that show the three puffin crossings at the Vale Road end of Mitton Street nor the one crossing Mitton Street at Severn Road and thus, if I'm not mistaken, the public has had no opportunity to object to this proposal.

But hey it's all going to be okay because they've modelled it using real data -

"So what if the model or the data is wrong; what if it all becomes one big mess; is there a process to have these removed?" I asked
"But the model won't be wrong; if it is there's bigger concerns" came the reply.
"But what if it is? Is there some method of having it all taken away?"

But so long as the data is reliable there's no problem; expect how good is it? For example queues form along this stretch of the road. Given road counters that measure traffic flow over them how does such a counter distinguish between a queue of traffic whereby the queue only progresses by one car every 10 seconds and a free-flowing stream of traffic with the cars separated by 10 seconds of time?