Wide lines, tight lines, right lines - the
law of Diminishing Returns
When I did the Bikesafe course back in October last year, one of the
very few negative comments on the day was the way the police rider
out with us held a wide line, out on the white line, round left hand
bends even though there was traffic coming the other way.
The argument resurfaces from time to time on Visordown.com as other
riders watch a copper doing exactly the same.
One resulting discussion produced some comments that surprised me,
the one that caused the most consternation was the suggestion that
by keeping wide if a half-second extra view could be obtained, then
it was worth it.
The other was that I over-complicate things. Sometimes I wonder if I
really AM awkward... and then I remember how many riders are killed
The crux of the matter was a statement by another instructor:
"There are times when position for view is the last thing (but not
'final') to be considered. Narrow lanes, tight blind corners? Forget
'progress', hug the left verge."
I agreed that seeing the spiky thing that impales you on the front
of the tractor a fraction of a second earlier is no use to anyone.
Then up popped a third instructor with:
"seeing something half a second earlier CAN make a differance. What
is important is that your speed is right such that you are able to
deal with any situations as they occur.
"Very often people are simply carrying too much speed as opposed to
being in the wrong position. The 2 combined are a lethal
combination, 2mph can be tioo much, just lose it and manage the
This caused me some consternation. I replied:
"There's an inverse relationship between the added time your
position gives you and the distance you have to stop/swerve even if
you reduce your speed. Diminishing returns..."
The more gentle the left hand bend, the more time you have to see
the oncoming car and vice versa and the more confidence I'll have in
a wide line being safe. But...
...the problem arises not only on single track lanes but also on a
road with two narrow (but still defined by a central line) lanes
with a very sharp left kink (not necessarily a right angle, it could
be a 45deg elbow) with obscured view (often a building at a "pinch
point" - there is a classic example on the A338 north of Wantage)
where the oncoming driver will not be seen till the last moment and
may be cutting the corner.
In some ways, an "elbow" bend is worse - it positively encourages
corner cutting from the opposite direction. So you have to bear in
mind the other driver's possible approach to the bend too.
For the moment, let's just take a middle of the lane path and just
consider if we can stop - because as we know, we should be able to
stop in the distance we can see to be clear. For most drivers and
riders, the two second rule isn't actually enough, because they need
recognise what they are seeing and then time to think of the correct
response. So add another second. That's the kind of view in terms of
time that the basic stopping rule would suggest we need to safely
negotiate a bend at 30mph.
So, let's find out what distance is involved were we to measure it
out. At 30mph, that's 132 feet or 40 metres of distance we need to
deal with a STATIONARY object - nearly half the length of a football
Now consider a vehicle on a collision course - that car that cut the
corner. Assuming the driver responds in the same way and stops, and
isn't going any faster than us, you've now got 20m to stop from
30mph. It's gonna be tight even if we are already covering the
brakes and poised to do an emergency stop! Is the other guy thinking
Unlikely - I can easily work out that other drivers aren't likely to
take as much care as me so the chances of meeting someone head on
are quite high! There is nothing I can do to manage their speed or
course. So it's not a risk I can manage.
Now let's consider the "Health and Safety" type assessment of that
risk. If I go round that corner on a line which may conflict with an
oncoming car cutting the corner, and the other driver is travelling
too fast to stop in his own "clear" distance, and I'm hit, then the
implications of a collision and its effect on me are fairly serious.
And there is a further consideration. If we put the brakes on hard
in a left hand bend, the bike sits up and goes where? Straight onto
the other lane, quite likely into the path of the driver who has
swerved to avoid us!
So do we have an alternative strategy for getting out of trouble? We
could swerve left, couldn't we? Hold onto that thought for a moment.
Let's go back to the view round the corner. What if we can squeeze
an extra half second view by moving 2m to the right, by taking a
course out by the white line? Well, that gives us an extra 22ft or
7m view. So we each have 3.5m extra to stop or swerve. Stopping is
still a no-no in the bend, particularly as you are now even more
exposed. Swerving is still probably your best option but now you
have to swerve an extra 2m to the left to avoid the car - and only
3.5m in which to do it. And think on this too - is the driver coming
the other way more or less likely to panic when he sees a bike in
the middle of the road rather than in the centre of the other lane?
So, is half a second really enough time to be useful? The answer to
that is a resounding NO!
So any other alternative strategies? If I take a tighter line out of
the likely course of anyone cutting the corner, I need to consider
that takes me closer to hazards on the left.
Now let's do another risk assessment. First thing I can say is that
any hazard on my side of the road isn't likely to be moving at
anything like the speed of something on the right - even an emerging
car is almost always heading laterally across your path and not
towards you - thus any collision is likely to have less serious
implications for me. (Compare
the results of "car emerges from left" vs "car turns right across
bike's path" type accidents).
What are the additional hazards of moving left? I've can think of a
number, but for argument's sake let's consider pedestrians. I can
assess the kind of road and the likelihood of coming across a
pedestrian. In a touristy area it's quite high. It's a risk I can
assess fairly easily. So, I simply adjust my speed so I can stop
before I hit a pedestrian or emerging car.
Say I move two metres left and say I lose one second of my three
second view, so I can only see 88ft / 27m ahead. If I'm on the ball
I can still stop at 30mph!! But because I am a sensible rider, I
take 10mph off the speed. I'm now well ahead of the game and can
stop easily should I meet a pedestrian or emerging car.
Is that not an advantage? So is not the tighter line safer to the
point where there is relatively little risk of any collision at all?
Have I not eliminated a big risk I can't control (ie - the oncoming
car that can't avoid me) and substitued a smaller risk I can do more
to control by my own actions (ie - avoiding running over a
And one final point. For how LONG in real terms are we going slower?
A couple of seconds in the tightest part of the bend? Is it going to
materially affect our journey time?
I'm not saying that you should take a tight line on all bends, as
the proponent of the half-second extra view seemed to think, but
that we question where we can position to advantage and use the
extra view and when it's time to change your line when faced with a
Sometimes we need to sacrifice position and view simply to be in a
safer place per se. What we have to work out is where the crossover
is from advantage to risk. I know we are talking about narrow roads,
tight turns, very restricted views which are at one extreme of a
continuum with wide sweepers at the other end, and most riders
rarely venture onto those kind of roads, but I do quite a lot and I
see some crazy lines.
The conclusion I draw from this says to me that post test training
doesn't emphasise the risks enough - after all we can only know what
is good and bad when we know the risks as well as the advantages,
and I think we are too much concerned about "advantage" and
I know I haven't persuaded the other instructor, and he certainly
hasn't changed my mind, but to my mind the important thing is that
the debate opens up the issue to people who use wide lines but may
not have thought about the special problems of tight bends, and to
those who may not have used wide positioning in the past thus giving
them a chance to see the advantages. And it was noticable that the
non-expert opinion was with the tighter line.
Give them the information, let them make their own informed choice.