" Gridlock " !

[Was92now625]

Birmingham has come close to "gridlock" the past couple of days, after an unexploded WW2 bomb has caused police to keep the Aston Expressway and Lichfield Road closed. This hasnt been helped by muppets who get impatient and block junctions. Seeing pictures of a completely empty A38(M) is quite strange.

I don't drive in Birmingham very often but I did so yesterday. It seemed that the roundabouts were the element of the network that could not cope.

[brummie_rob]

The traffic maps yesterday were some of the worst I have seen in the city, even when there have been snow events. Took one of our staff three hours to get home on a 30 minute journey.

[Was92now625]

The traffic maps yesterday were some of the worst I have seen in the city, even when there have been snow events. Took one of our staff three hours to get home on a 30 minute journey.

After about 20 minutes covering 100 yards, I resorted to "I'll find a direction, any direction, that looks a little less congested, drive for a few miles that way, and sort things out later !" Aston to Bromsgrove via Solihull !

[Peter Freeman]

Taken literally, gridlock is an American term which only works in places with grid road layouts. It is when a queue meets its own tail, preventing the back of the queue from moving.

Actually the problem is when a queue meets its own tail, preventing the front (and therefore the whole queue) from moving.

Roundabouts and gyratories can be "prone to gridlock" if too many vehicles enter them and not enough can leave.

A roundabout could experience true gridlock if the 'give way to right' rule was disobeyed, especially if simultaneously so on two or more of its entrances. That was one of the reasons for the rule's introduction (or formalisation) in the 1960's. "Not enough can leave" should eventually self-resolve, so that is not true gridlock unless there is a second continuous and locked circuit that is separate from the roundabout.

The same goes for any similar layout, including a dual carriageway with two busy right turns.

Yes, opposing right turns can cause true gridlock when following the UK rule that right-turners must go behind each other. In AU and USA right turns are performed passenger-side-to-passenger side, so those manoeuvres can proceed continuously. The visibility problem (which is the reason for the UK rule) is, in practise, carefully worked around.

(edited only to clarify: 'reason')

[lefthandedspanner]

Roundabouts and gyratories can be "prone to gridlock" if too many vehicles enter them and not enough can leave.

Or if there's a pelican crossing five yards from one of the exits, which force everyone on that side of the roundabout to stop when the lights go red, blocking any entrances on that side and preventing anyone from turning across the roundabout.

[A9NWIL]

Roundabouts and gyratories can be "prone to gridlock" if too many vehicles enter them and not enough can leave.

Or if there's a pelican crossing five yards from one of the exits, which force everyone on that side of the roundabout to stop when the lights go red, blocking any entrances on that side and preventing anyone from turning across the roundabout.

Thats a pet hate of mine, pedestrian crossings just off roundabouts! They should be 100-200 metres away from the junction with just a pedestrian refuge area close to the roundabout.
That way motor traffic has the priority coming off the roundabouts, but there is provision for pedestrians in two ways.

[Peter Freeman]

Or if there's a pelican crossing five yards from one of the (roundabout) exits, ...

But that's temporary gridlock, and will self resolve when the ped crossing lights change to green. It's a nuisance, but peds must be considered.

[Fenlander]

It also puts a temporary stop on circulating traffic which can mean a gap for someone else downstream to use. The zebra here backs up onto the roundabout and temporarily stalls that flow, if you pan round you'll see stopped traffic on the roundabout due to the traffic light controlled crossing the other side of it which has a longer lasting effect.

[Berk]

Or if there's a pelican crossing five yards from one of the (roundabout) exits, ...

But that's temporary gridlock, and will self resolve when the ped crossing lights change to green. It's a nuisance, but peds must be considered.

Yes, but they tend to have priority when lights sequences are concerned. Peds and minor roads pretty much get priority, to the detriment of the mainline.

[AndyB]

I'm sorry, but I don't believe that is true. Ped lights spend far more time with the lights at green for road traffic than all other states put together, while detection systems far too frequently make the pedestrians wait until they could have crossed using the Green Cross Code, and while any given minor road at a traffic light controlled junction may seem to get a green light on demand, they still get green lights for far less time than the main road, mainly because the lower traffic volumes take less time to clear.

It's also worth pointing out that holding traffic on a side road for an extended period is likely to lead to other problems due to queuing traffic.

[ais523]

As someone who uses the road system a lot as a pedestrian… there are some light-controlled crossings which give pedestrians priority (i.e. pressing the button is guaranteed to stop traffic immediately unless it was stopped very recently), but they're very much in the minority. Most pedestrian crossings will wait until a gap in the traffic large enough to not need the crossing in the first place, with a fallback to stopping the traffic after a couple of minutes if no gaps opened up. (At a junction, rather than a peiican crossing, sometimes a "pedestrian phase" is added into the normal sequence, and skipped if the buttons aren't pressed.)

[brummie_rob]

'Gridlock' in Stoke-on-Trent today as the A500 has been closed since 5am this morning after a broken down lorry was ploughed into by another. Sadly the driver died who went into the broken down lorry.

Problem is, nearly 12 hours later it is still shut. The actual damage was mainly the second lorry, so recovery must have shifted them but the investigation is taking ages. Surley it is a clear-cut case of a driver not paying attention. I've seen worse accidents cleared quicker.

Wasn't helped by a closure of the M6 from J15-J16 with the A500 being the typical diversion bringing the area to a halt.

[Johnathan404]

Surley it is a clear-cut case of a driver not paying attention. I've seen worse accidents cleared quicker.

While I appreciate traffic chaos is frustrating for those affected by it and venting about it does help, for everyone else armchair-expertise like this can be pretty irritating. You have effectively said that from a quick glance at the scene or reading a news report you now know all the circumstances of the event.

[Arcuarius]

Problem is, nearly 12 hours later it is still shut. The actual damage was mainly the second lorry, so recovery must have shifted them but the investigation is taking ages. Surley it is a clear-cut case of a driver not paying attention. I've seen worse accidents cleared quicker.

Sorry but you don't know what caused it.

It could have been brake failure, or he might have hit a patch of ice. There was a frost this morning. That's exactly what the investigation is there for, and why it takes that long.

And I'm sure if it was your family member that was killed, you'd want to know exactly why, rather than rely on third-rate guesswork from a local news report.

After all, I'm sure you can cope with being delayed a bit...

[avtur]

Problem is, nearly 12 hours later it is still shut. The actual damage was mainly the second lorry, so recovery must have shifted them but the investigation is taking ages. Surley it is a clear-cut case of a driver not paying attention. I've seen worse accidents cleared quicker.

Sorry but you don't know what caused it.

It could have been brake failure, or he might have hit a patch of ice. There was a frost this morning. That's exactly what the investigation is there for, and why it takes that long.

And I'm sure if it was your family member that was killed, you'd want to know exactly why, rather than rely on third-rate guesswork from a local news report.

After all, I'm sure you can cope with being delayed a bit...

+1 agree with @Arcuarius ... there is only once opportunity to collect evidence at the scene, it has to be done in order to have the greatest chance of arriving at the true root cause. If it is clear that there is a fatal outcome, or it is "likely to prove [fatal]" the most thorough level of investigation is appropriate, even if it causes frustration to others.

[Bryn666]

Maybe with all the cuts to police funding the few collision investigators remaining In each force area couldn't get there immediately meaning the scene has to be preserved.

Having been caught up in it I still am not griping because collision investigation has to be done and if it takes 3 days then so be it.

[Berk]

Surley it is a clear-cut case of a driver not paying attention. I've seen worse accidents cleared quicker.

While I appreciate traffic chaos is frustrating for those affected by it and venting about it does help, for everyone else armchair-expertise like this can be pretty irritating. You have effectively said that from a quick glance at the scene or reading a news report you now know all the circumstances of the event.

Well, if it is a simple case of driver error, why the need for a forensic investigation?? OK, you would discover whether there was a mechanical failure on the second driver’s cab/convoy.

But I would argue, is it worth waiting 12-15 hours to discover facts that in all probability could be deduced away from the roadside?? I think investigations should only take place at the roadside where the evidence is completely unclear and further investigation is essential.

Taxpayers need to ask if multi-hour road closures and forensic investigations are worth spending £1000s (and it will be thousands) of police resources on, when budgets are so tight. Not resorted to as a default course of action.

[Berk]

Maybe with all the cuts to police funding the few collision investigators remaining In each force area couldn't get there immediately meaning the scene has to be preserved.

Having been caught up in it I still am not griping because collision investigation has to be done and if it takes 3 days then so be it.

3 days, a week, a month?? It’s not like there are other dangerous people out there is it??

[Arcuarius]

Surley it is a clear-cut case of a driver not paying attention. I've seen worse accidents cleared quicker.

While I appreciate traffic chaos is frustrating for those affected by it and venting about it does help, for everyone else armchair-expertise like this can be pretty irritating. You have effectively said that from a quick glance at the scene or reading a news report you now know all the circumstances of the event.

Well, if it is a simple case of driver error, why the need for a forensic investigation?? OK, you would discover whether there was a mechanical failure on the second driver’s cab/convoy.

But I would argue, is it worth waiting 12-15 hours to discover facts that in all probability could be deduced away from the roadside?? I think investigations should only take place at the roadside where the evidence is completely unclear and further investigation is essential.

Taxpayers need to ask if multi-hour road closures and forensic investigations are worth spending £1000s (and it will be thousands) of police resources on, when budgets are so tight. Not resorted to as a default course of action.

The default course of action is for it to take exactly as long, and cost exactly as much, as it needs to. And rightly so, too.

I have no time for selfish armchair "experts" who only mind because it delays or diverts them a bit. Just put yourself in the position of that poor guy's family. Or the driver of the HGV into which he crashed. I'd bet you anything that you would want to know why his life needlessly ended too soon.

[Bryn666]

Do you say the same if someone dies in an industrial incident or on a railway?

It is a requirement of the law that proper investigations are taken to determine if a criminal act resulted in a death.

How do you determine if braking was applied from the roadside? Or where the vehicle came to a halt or distance travelled etc. The police would very strongly disagree with anyone suggesting "sweep the dead to the side and reopen the road" even if they only had 12p to do their work.