What speed should I plan on a sliproad?

[supermono]

Following on from an incident where I had to accelerate from my 70mph sliproad speed to 10/20mph over the speed limit to access the clear road ahead of lane 1 trucks well before they reached the end of my sliproad, I've learned to join more slowly so that I won't speed at any point if I need to accelerate and to allow the option of slowing down a bit to join behind or in a small gap between traffic.

But what speed should I aim for? 50? 60? Something else?

SM

[Engineer1]

speed for joining a road from a slip road should be such that you slot into a gap, if the motorway is doing 50 then join at 50ish, if it is doing 70 try and join at 70ish, spot the gap you want then match your speed to enable you to put your car into that gap.

[supermono]

Engineer1 said:

speed for joining a road from a slip road should be such that you slot into a gap, if the motorway is doing 50 then join at 50ish, if it is doing 70 try and join at 70ish, spot the gap you want then match your speed to enable you to put your car into that gap.

The problem I had was a line of trucks with no viable gaps doing ~50/55mph. Me and following car doing 70mph but I mistakenly sped up to access the clear road ahead of trucks.

My advanced friend suggested that if I'd been going slower I could have slowed down more easily to access whatever gap might exist between the trucks or behind them.

He didn't suggest the speed though, just slower.

SM

[p1esk]

supermono said:

Engineer1 said:

speed for joining a road from a slip road should be such that you slot into a gap, if the motorway is doing 50 then join at 50ish, if it is doing 70 try and join at 70ish, spot the gap you want then match your speed to enable you to put your car into that gap.

The problem I had was a line of trucks with no viable gaps doing ~50/55mph. Me and following car doing 70mph but I mistakenly sped up to access the clear road ahead of trucks.

My advanced friend suggested that if I'd been going slower I could have slowed down more easily to access whatever gap might exist between the trucks or behind them.

He didn't suggest the speed though, just slower.

SM

I think you could do it either way, except you may prefer to avoid the speeding. To be honest, if I could accelerate to get ahead of the line of trucks, even if it involved a bit of speeding for a short distance, I'd do it that way and get the job done. Alternatively, you could slow down and get in behind the line of trucks if it looks like a suitable gap might be available there.

Again, you might try matching speed with the trucks part way up the line, getting as close to them laterally as feels comfortable, and doing it as soon as the slip road permits it. Then if you hang about in that position you may find one of the nearby truck drivers will open up a gap and let you in. In most cases I find people generally fairly willing to help in that way. I think maybe they see me struggling and take pity on me.

In any case I think it's worth deciding how you're going to set about it as early as possible, to avoid running out of slip road before you've found a way in.

Best wishes all,
Dave.

[Vaux]

supermono said:

The problem I had was a line of trucks with no viable gaps doing ~50/55mph. Me and following car doing 70mph but I mistakenly sped up to access the clear road ahead of trucks.

My advanced friend suggested that if I'd been going slower I could have slowed down more easily to access whatever gap might exist between the trucks or behind them.

He didn't suggest the speed though, just slower.

I'd suggest around 55, the speed of the trucks, so you can slow or speed up a little to get into a gap. If they won't open up a gap you're stuck at the give way line, but that would be rare, as you would appear to be trying to merge nicely, rather than forcing your way in.

[PeteG]

Aye, about 50-55mph seems about right - then by leaving it in third, you can accelerate ahead of any traffic, or use engine braking to slow down and slot in behind - as soon as the view opens up, choose your gap.

[Pigeon]

supermono said:

The problem I had was a line of trucks with no viable gaps doing ~50/55mph. Me and following car doing 70mph but I mistakenly sped up to access the clear road ahead of trucks.

My advanced friend suggested that if I'd been going slower I could have slowed down more easily to access whatever gap might exist between the trucks or behind them.

He didn't suggest the speed though, just slower.

I don't know the distances between vehicles in this case but in general it seems to me that effectively racing the trucks to the merge point at the end of the sliproad where it finally disappears is a manouevre with significant potential to go wrong if you misjudge the speeds/distances and don't make it.

It's more likely to be preferable to ease off and look for a gap further back, then choose your speed so as to be able to slot into this gap at the start of where the sliproad joins the carriageway. If this doesn't work out you still have the length over which the sliproad still exists before it finally merges to take corrective action.

You can't really prescribe a speed as it'll depend on individual circumstances, and even in particular circumstances it'll be "slower" rather than a specific speed because that's how human perception and communication works.

[BOR]

My own method is to merge at a much higher speed than the other traffic. Why ? Mainly it avoids the situation where the gap that you want to merge into gets closed up by the leading and following cars - you have limited control over this. If you have the option to accelerate hard past other traffic - eg trucks, you have a better view of the gap availability and less chance of being shut out.

[Vaux]

Pigeon said:

You can't really prescribe a speed as it'll depend on individual circumstances, ....

On a free flowing motorway, lane 1 full of LGVs, they'll be doing 55ish.
I thought this was the scenario being discussed?

[fat80b]

BOR said:

My own method is to merge at a much higher speed than the other traffic.

I agree to approach the slip road at a higher speed than the moving traffic.

In general, this is because it is easier to brake to adjust your speed to "slot in" than to accelerate (depending on vehicle)

If I was in the g'f s 1.2 clio trying to out gun a trail of HGV's from an almost standing start, I would be in a bit of trouble,

Bob

[GreenV8S]

If you're hoping for cooperation from the traffic in lane 1 to enable you to merge, it's better to be going slower than them rather than faster. It gives you more time to negotiate with them, and given that drivers tend to see forwards better than backwards it gives you a better chance that they will notice you when you approach them from in front. I think they might also be less inclined to cooperate if they perceive you as trying to undertake them and then push in.

[timskipper]

But what if it's apparent that traffic conditions will allow you to either a) get your welly down and get out safely in front (albeit at an illegal speed) or b) probably have to come to a complete stop at the end of a slip-road. I've seen and been in this situation so I know it happens.

Surely safety trumps the letter of the law to anyone with half a brain? But the thread to which the OP alludes seemed to suggest from a serving offiver that it should not.

Personally I'd rather have a conversation with John Law by the side of the road further on than end up picking bits of car out of my backside.

[crisisjez]

Assesment and early planning, if you need to go fast...go fast, if slow... go slow.
Never expect to be let out and you`ll never be caught out.
Speed is as much a tool of safety as braking is, and both can also cause accidents.
In answer to your post though.........
How long is a piece of string!!!!!!!

[JP_Midget]

I find the best way is to make room in front while on the slip road, which can see me having to do speeds down at 40 because the car ahead is being too timid about joining the motorway. Then I want to be approaching at 50-55 as I know I can speed up to 65-70 fairly quickly from there if needed. Going a bit slower initially allows you more time to assess the density of traffic and its speed. It's frustraiting when there is a row of trucks all 4 feet from the one in front just when you want to join, but if you accelerate to get in front you're approaching vehicles that might not have seen you coming from their nearside rear, plus people already on the motorway that are overtaking the trucks may pull to the nearside lane just as you make it at speed ahead of the truck and try to do the same.

[Sharief]

My driving instructor always said 60mph in 3rd gear for joining onto a free-flowing dual carriageway/m'way.

[thiscocks]

There is no set speed, just get to the speed the slow lane is doing, and slot into a safe gap. Simple.

[Sharief]

thiscocks said:

There is no set speed, just get to the speed the slow lane is doing, and slot into a safe gap. Simple.

Yes but surely there's no point pootling down to end of the slip road in your car at 30mph, then realising everyone's doing 70. Surely you should plan generally for around 60mph?

[7db]

As said earlier - the biggest pedal in the car is the brake. A little quicker, but with the proviso that you're not depending on anyone else in the slip lane. If I have one in front on the slip, I'll hang back a bit to give me space ahead for when I join.

[GreenV8S]

Sharief said:

Yes but surely ... you should plan generally for around 60mph?

I'd say that you should plan to be at an appropriate speed for the circumstances, sometimes 60 mph might be appropriate, that doesn't mean you can be prescriptive and say 60 mph is always the right speed.