Locking wheels and RLJing

[martint235]

One thing that has been done recently in some areas is to decrease the amber time, this means there is often a zone where you have to be doing significantly less than the speed limit if you don't want to run a red light without having to do an effective emergency stop. You can argue all day long that you should slow down etc. but if the speed limit is 30mph then the amber phase should be long enough that it does not require very heavy braking to stop from that speed to avoid going through a red light.

But should you be driving at the speed limit on the approach to traffic lights? They didn't just appear overnight, you know they are there prepare for them to be red.

I saw an IAM guy on telly a few years back who said that there is only one colour of traffic light where you shouldn't be preparing to stop and that's red cos you should already be stationary.

 

[NigC]

If you think that braking could cause an accident to either yourself or other traffic then you can RLJ.

Yes you are.

Can't see that standing up in a Court of Law, could you?

"Yes your honor, i know i ran through a red light, knocking that person over and causing them sever injuries but i was traveling too fast to brake in time".......

Can't see it myself.

There's a big difference between not being able to stop because you're too close (and of course, within the speed limit) to the lights as they turn amber (which does mean stop) and running a red light at speed (which will have been red for some time for people to have started crossing). There is a significant pause between traffic lights going red and crossing lights going green that allows for a can't-stop-too-close-to-lights scenario.

The problem with a bicycle is that the can't-stop-too close-to-lights speed is lower than a cars, which could potentially mean going through on red, or even amber, for a cyclist may not give them enough time to get clear of traffic that has then got right of way. So a cyclist should prepare for traffic lights much sooner by making sure they can stop the instant they see amber.

 

[GrasB]

But should you be driving at the speed limit on the approach to traffic lights? They didn't just appear overnight, you know they are there prepare for them to be red.

This actually is irrelevant because an artificial & controllable situation has been engineered where some driving legally, though not to the best driving standards, is put in a position where they can't obey the law with out aggressive use of the brakes & performing a near emergency stop. Aggressive braking causes problems, it puts far more strain on the road surface (which means that over time the surface will degrade more & braking distances increase causing the initial problem to become worse), it may alarm people in the immediate area, can catch people by surprise & in the worst case causes loss of control.

 

[Jezston]

Amber lights tend to display for, what, two seconds or so? How fast would you have to be going on a bicycle or how bad would your brakes have to be to not be able to comfortably come to a stop in that period of time?

Maybe I've just not ever found myself in a position where I have felt it unsafe to stop at a set of lights, or maybe i'm just slow and spoilt by disc brakes.

 

[martint235]

This actually is irrelevant because an artificial & controllable situation has been engineered where some driving legally, though not to the best driving standards, is put in a position where they can't obey the law with out aggressive use of the brakes & performing a near emergency stop. Aggressive braking causes problems, it puts far more strain on the road surface (which means that over time the surface will degrade more & braking distances increase causing the initial problem to become worse), it may alarm people in the immediate area, can catch people by surprise & in the worst case causes loss of control.

Sorry but I don't see it as irrelevant. Just because the situation has been engineered doesn't mean that someone is pushing the driver's (or cyclists) foot to make them go faster. A speed limit is just that, a maximum speed for that area, not a recommended speed.

 

[jeltz]

The way I see it, if I could only just maintain control and stop in time I'm travelling a touch too fast.

I don't think I would be considering the relative merits of whether its better to jump the lights or not, I'd be making a mental note to not gun it down the hill quite so fast next time.

 

[Arch]

I sometimes mentally 'tick off' the point at which I'll keep going if the lights change to amber - it's pretty close to the line. Up to then, I'm covering the brakes, expecting to have to stop. After it, I give it a bit of welly to get clear.

 

[Lizban]

Traffic Lights are a Hazard (and a predicatable one) a prudent cyclist would be expected to be able to stop safely when they go amber to red.

If you can't you are going too fast, simple.

You should be slowing down anyway as they are hazard

 

[BenM]

A rear wheel skid is not much fun on a 'bent bike... kind of hard to control so I always assume the lights in sunny Weymouth will be red. They usually are, and even those which are green change to red almost instantly

B.

 

[karan733]

Just to wade back in, I was only doing around 20-25, based on this being a 30 road and cars only just passing me rather than speeding past. If there are a lot of cars I can also usually keep up with them as they arent doing 30. I also hit both brakes when the lights turned amber, and at that point I was just behind the bus stop area. And just to reiterate, I stopped at the line, and did not RLJ. But I was just about in control of the bike, and this probably wasnt great for the bike/wheels either.

I think if I was in the same situation again and there wasnt a ped, Id hit the brakes and then run the light if I wasnt scrubbing off enough speed rather than take those kinds of risks

 

[Arch]

I think the bike's speed relative to the limit, and to other cars, is irrelevant. If your safe stopping distance is longer, then your safe top speed in an urban area is less... I think even if I was capable of sustaining 25mph, I wouldn't in town, because there are hazards and potential emergency stops so often.

 

[tdr1nka]

It's simply an issue of judging your speed and ability to brake to fit the conditions.

If you find the back wheel getting twitchy then 'feather' the rear brake, sqeezing it on and off but not so heavily that it locks up.

I find if a situation like that shakes you up a bit then you were probably going too fast.

 

[GrasB]

karan733, I think one of the mistakes you made was actually using the back brake. Under heavy braking I tend to find the rear brake does nothing but increase the stopping distance as you have to control rear brake away.

martin, Simply put you should expect to have people travelling at the speed limit & if the lights are phased in such a way that people have to make a aggressive control input, braking in this case, to stop in time the speed limit is now inappropriate. You see as the amount of time you have to stop is actually hidden, it's not like a corner where you can see how sharp it is, driver has no idea that actually they need to be travelling at 20mph to not jump the red light or stop very quickly.

Traffic Lights are a Hazard (and a predicatable one) a prudent cyclist would be expected to be able to stop safely when they go amber to red.

If you can't you are going too fast, simple.

You should be slowing down anyway as they are hazard

I agree up to a point, if it's a light you encounter regally then then there's no excuse for not knowing how much time you'll have to stop. The problem is you come up to lights you don't normally come across have to 'guess' how long you'll have to stop. If you ones with a short amber phase you're not going stop in time.

 

[martint235]

martin, Simply put you should expect to have people travelling at the speed limit & if the lights are phased in such a way that people have to make a aggressive control input, braking in this case, to stop in time the speed limit is now inappropriate. You see as the amount of time you have to stop is actually hidden, it's not like a corner where you can see how sharp it is, driver has no idea that actually they need to be travelling at 20mph to not jump the red light or stop very quickly.


I agree up to a point, if it's a light you encounter regally then then there's no excuse for not knowing how much time you'll have to stop. The problem is you come up to lights you don't normally come across have to 'guess' how long you'll have to stop. If you ones with a short amber phase you're not going stop in time.

I agree with to a point. If you're on a strange road with signs marking it as 30mph and you're within this limit then quick changing lights could be an issue. I think there could be an issue here with if it's a strange road, should you be going that quickly with no idea of possible problems, road surface etc.

However in this instance, I believe the OP was going to quickly. It's a road they appear to know fairly well and "usually" travel at 20-25mph down so they should, imo, have been prepared for a red light without the need to skid the back wheel.

 

[NigC]

karan733, I think one of the mistakes you made was actually using the back brake. Under heavy braking I tend to find the rear brake does nothing but increase the stopping distance as you have to control rear brake away.

martin, Simply put you should expect to have people travelling at the speed limit & if the lights are phased in such a way that people have to make a aggressive control input, braking in this case, to stop in time the speed limit is now inappropriate. You see as the amount of time you have to stop is actually hidden, it's not like a corner where you can see how sharp it is, driver has no idea that actually they need to be travelling at 20mph to not jump the red light or stop very quickly.


I agree up to a point, if it's a light you encounter regally then then there's no excuse for not knowing how much time you'll have to stop. The problem is you come up to lights you don't normally come across have to 'guess' how long you'll have to stop. If you ones with a short amber phase you're not going stop in time.

I think the time of the amber phase is a red herring. Amber and red both mean stop regardless of how long they stay that colour.

Everyone should also be aware enough of their own limitations with regard stopping distance. It's simply a case of going at a speed where you know you can stop comfortably when you're approaching traffic lights or other junctions.