S3 Suicide lane

[Glen]

Well, the majority of drivers are probably numpties who daren't overtake anything quicker than a tractor. But does that mean that overtaking opportunities should be deliberately removed for those who can?

If you drive on the A9 you will see that at the start of a two lane section most cars dive into the overtaking lane so you get a line of cars doing about 60mph crawling past a lorry doing 56mph for the entire length of the overtaking lane, so most people will overtake (if they see the need) if they have a guaranteed opportunity.

The point is that it is easier to drive a road with decent lane widths rather than in narrow lanes where you are constantly watching your position in relation to passing traffic, more so if there is a frequent line of overtaking traffic.
I would suspect that narrowing the lanes to squeeze another in would actually create an additional hazard that would slow the flow of traffic down.
If it wasn't for the Talivans, lorries would comfortably sit at 56mph on a decent S2 like that, but squeezed into a lane that is not much wider than the vehicle they would slow down.So if you were on the one-lane side you would end up doing under 45-50 without being permitted to overtake, rather than flowing at 50-56 with the opportunity to pass if safe.

[hughster]

Well, the majority of drivers are probably numpties who daren't overtake anything quicker than a tractor. But does that mean that overtaking opportunities should be deliberately removed for those who can?

If you drive on the A9 you will see that at the start of a two lane section most cars dive into the overtaking lane so you get a line of cars doing about 60mph crawling past a lorry doing 56mph for the entire length of the overtaking lane, so most people will overtake (if they see the need) if they have a guaranteed opportunity.

The point is that it is easier to drive a road with decent lane widths rather than in narrow lanes where you are constantly watching your position in relation to passing traffic, more so if there is a frequent line of overtaking traffic.
I would suspect that narrowing the lanes to squeeze another in would actually create an additional hazard that would slow the flow of traffic down.
If it wasn't for the Talivans, lorries would comfortably sit at 56mph on a decent S2 like that, but squeezed into a lane that is not much wider than the vehicle they would slow down.So if you were on the one-lane side you would end up doing under 45-50 without being permitted to overtake, rather than flowing at 50-56 with the opportunity to pass if safe.

I still feel that this is only true if the road is not exceeding the maximum capacity of that class of road. If it is, you may have nice wide lanes and shoulders, but you can't "flow at 50-56" because you're always stuck in slow-moving queues with no possibility of overtaking. Adding alternating crawler lanes would surely provide a net benefit in those instances.

I agree with you that comfortably wide S2 routes should not be converted to S2+1 as a matter of course simply to provide overtaking opportunities.

[skiddaw05]

The A149 Queen Elizabeth Way does annoy me - I drive it regularly, and it was about 15 year ago that it was relined.

It should have been set to alternate priority when overtaking retaining the three lanes - very annoying what's been done with it!

The focus of attention on the King’s Lynn eastern bypass (A149 QE Way) has caught my eye. The situation here has evolved over the years. On a general note the S3 has been taken out for the fairly obvious reason that the road had a terrible safety record. It wasn’t helped by the tidal nature of the traffic in the summer months where drivers going in the direction of the dominant flow would take possession of the middle lane, sometimes with the help of headlamps to reinforce their supposed right to have priority.

The flow is more even now I reckon, and certainly it’s more busy and there is almost continuous traffic a lot of the time. With this, and the relatively short distances between roundabouts (no more than 3km apiece), I do not think an S2+1 would be appropriate. A reasonable proportion of the length would have to be taken by the crossover section (hatching), and the merging of lanes would just cause traffic to back up, just like it does now at the merge from the Hardwick roundabout. And it would, without a shadow of doubt, be more dangerous than it currently is

Anyway, a bit of history: The first change was on the curved section south of the B1145 roundabout, where central hatching was put in sometime in the mid 80s, whilst the rest remained S3. Later (early 90’s I think) the remaining centre lane was removed. However it started off as a WS2 – the inner edge lines as shown on Truvelo’s photo weren’t put in until later – and it was still treated much like the old S3.

Things are set to get worse: next year a new roundabout is to be built about 1km north of the Hardwick as part of the new Sainsbury’s store which is going to be built next to the Pinguin Foods factory. Be afraid.

[hughster]

Things are set to get worse: next year a new roundabout is to be built about 1km north of the Hardwick as part of the new Sainsbury’s store which is going to be built next to the Pinguin Foods factory. Be afraid.

They'll certainly have to upgrade the road when doing that, as the AADT on that section south of the Hospital is already over 24,000, which I believe is 3,000 over the maximum recommended for WS2. It would probably have to be D2.

[skiddaw05]

Alas I can assure you that, apart from a slight increase of the merge length off the Hardwick, there are no plans to do anything at all to the A149 either side of the new roundabout.

[hughster]

Alas I can assure you that, apart from a slight increase of the merge length off the Hardwick, there are no plans to do anything at all to the A149 either side of the new roundabout.

Then you're right -- we should be afraid. That stretch of road is already stationary on summer weekends; I can't imagine how it could get much worse. Some pointed comments on this local news article, and details of the planned roundabout here.

I won't comment any further here as it's slightly off topic now.

[c2R]

The flow is more even now I reckon, and certainly it’s more busy and there is almost continuous traffic a lot of the time. With this, and the relatively short distances between roundabouts (no more than 3km apiece), I do not think an S2+1 would be appropriate. A reasonable proportion of the length would have to be taken by the crossover section (hatching), and the merging of lanes would just cause traffic to back up, just like it does now at the merge from the Hardwick roundabout. And it would, without a shadow of doubt, be more dangerous than it currently is

Possibly... Perhaps just have the two lanes going northbound between the Hardwick roundabout and the A148 junction then, where much of the traffic turns off anyway - that would be an increase in capacity in one direction for very little cost. Northbound traffic does seem to be slightly worse than southbound for most of the day anyway, particuarly at weekends and in high holiday season with the amount of coast bound traffic travelling first thing.

Things are set to get worse: next year a new roundabout is to be built about 1km north of the Hardwick as part of the new Sainsbury’s store which is going to be built next to the Pinguin Foods factory. Be afraid.

They've got to be having a laugh to nod that through without a s106 to at least dual that stretch as well!!

[SteveA30]

Here is an S3 in action, on April 20 1960. The middle lane is hogged by the dominant flow so, probably safer when busy than when quiet when, either side could stake a claim.

The caption states A30 near Basingstoke but, in a new book about that era, from W H Smith, the caption reads A4 near Basingstoke. Note the many picnickers along the verge.

[Stevie D]

The flow is more even now I reckon, and certainly it’s more busy and there is almost continuous traffic a lot of the time. With this, and the relatively short distances between roundabouts (no more than 3km apiece), I do not think an S2+1 would be appropriate. A reasonable proportion of the length would have to be taken by the crossover section (hatching), and the merging of lanes would just cause traffic to back up

Simple solution - have the first half of the distance on leaving the roundabout as the '1' and the second half as the '2'. That way, you waste no space at the crossover, and the merge issues are dealt with at the roundabout. OK, you might need a wide flare to accommodate two lanes merging as they exit the roundabout, but that's small beer.

[Glen]

The overtaking lane should be leaving the roundabout so it works as a differential acceleration lane. Having an overtaking lane approaching the roundabout where there is only one lane after the roundabout encourages traffic to be approaching the roundabout at excessive speed and is likely to result in accidents as traffic attempts to complete overtakes.
Even though a conflicting changeover takes more space it is safer than merging at a roundabout.

The Clackmananshire bridge is laid out as you suggest, but one end leads onto a D2 and at the other the traffic flows split rather than most of the traffic continuing on a main route.

[hughster]

The overtaking lane should be leaving the roundabout so it works as a differential acceleration lane. Having an overtaking lane approaching the roundabout where there is only one lane after the roundabout encourages traffic to be approaching the roundabout at excessive speed and is likely to result in accidents as traffic attempts to complete overtakes.
Even though a conflicting changeover takes more space it is safer than merging at a roundabout.

Based on examples elsewhere (such as here and here), you'd only need 250-300 m of central hatching to allow for a conflicting transition. That would still allow 1.3 km of overtaking each way on a 3 km stretch of S2+1. To ensure no head-ons due to idiots overtaking on the hatching you could put in a brightly lit central island at the mid-point.

That being said, D2s often convert to S2 at roundabouts with one lane becoming a left/right-turn-only, which seems to work fine at slowing traffic down.

[WHBM]

They've got to be having a laugh to nod that through without a s106 to at least dual that stretch as well!!

Ah yes, Section 106 "Agreements". I wonder how those will sit with the new Bribery Act coming into force. For in truth that is what the "agreements" very often are.

[peterowan]

I've just posted this in the gallery - four lane single carriageway with overtaking allowed into the 3rd lane going uphill towards the summit. Bonkers?

[ajuk]

Why don't they go for WS2 or 2+1 alternating which side can overtake with only small sections hatched off for turning lanes?

[jcpren]

No need - it's four lanes wide.

[WHBM]

Why don't they go for WS2 or 2+1 alternating which side can overtake with only small sections hatched off for turning lanes?

The issue with most is that they are traditional all-purpose roads giving side access not only to every side lane but also to farm field gates etc, where such measures just do not work.

The A303 Ilminster Bypass and a few other similar ones are modern roads built in the 1980s which do not suffer from such issues and thus S2+1 becomes practical.

Furthermore, if you are going to put in such mainstream traffic management measures you need a good length to do so, especially at the transition points between opposing directions. One of the upsides of an S3 is you can mark out sections as short as you like before reverting to a central hazard line at side junctions, then a bit more S3. This was the common marking of them in the 1960s, and worked well to allow short-term overtakes of the likes of lorries, far smaller than nowadays in every dimension of course, which often then seemed incapable of more than 30 mph with any load on board.

[ScottB5411]

I've just posted this in the gallery - four lane single carriageway with overtaking allowed into the 3rd lane going uphill towards the summit. Bonkers?

Not that I would recommend it but overtaking is allowed in the 4th lane too heading away from the camera

[michael769]

Given the visibility and how long you would need to get from lane "4" back to lane 2 without cutting anyone up, I'd say that would not be legal. An offender would be looking at careless driving at best, dangerous driving more likely.

Frankly unless the traffic being overtaken was going at a crawl even lane "3" would see them in front of the beak.

Very odd arrangement - I suspect the council have mistakenly applied the TSM guidlines for 3 lane hills.

[chris486]

Given the visibility and how long you would need to get from lane "4" back to lane 2 without cutting anyone up, I'd say that would not be legal. An offender would be looking at careless driving at best, dangerous driving more likely.

Frankly unless the traffic being overtaken was going at a crawl even lane "3" would see them in front of the beak.

Very odd arrangement - I suspect the council have mistakenly applied the TSM guidlines for 3 lane hills.

This road is from the pre-motorway era and is not especially busy.

I suspect it might even have been repainted since the Google car's visit.

[PeterA5145]

Very odd arrangement - I suspect the council have mistakenly applied the TSM guidlines for 3 lane hills.

There are still S4 rural roads with dotted centre lines around - see here, for example. I think going back to the 1990s the 4-lane sections of the A556 were like that.