Joining a main road from a sliproad can be a dangerous and daunting task. One of my pupils got it very wrong today and nearly crashed.
(click to enlarge)
On this picture, we're travelling from the bottom right corner of the screen, joining the road heading towards the left hand side of the screen. We're travelling at close to the 40 mile per hour limit, and there's a car quite close behind us. On the main road, there's just one car, quite a long way back from the junction, but travellling quite a lot faster than the speed limit.
My pupil has a look over his shoulder, and sees the car in the distance, then has a couple of looks in his door mirror, but is unable to see the car. At this point, I don't know the car is there, and I'm concentrating on trying to get my pupil to give himself a wider field of view in his door mirror by leaning forward in his seat. As we approach the give way lines, I look to the side to find the car is almost alongside us. I immediately brake firmly and take hold of the wheel to stop my pupil from attemting to steer to the right. At the same moment, the car on the main road swerves sharply right to avoid us, and we miss each other. The person following us also has to brake sharply, and once things have sorted themselves out, he overtakes us on the main road. The driver of that car clearly thought it was the car on the main road that was at fault, and to an extent, he was.
There were two lanes available, and he was the only car on the road. He should have read the situation, checked his mirrors, and moved over into the outside lane. That would have allowe dthe traffic on the sliproad to safely join the main road. He was also travelling far too fast. Perhaps 60 miles per hour in a 40 limit.
But at the end of the slip road, there are give way lines. Drivers coming that way must give way to oncoming traffic. So we were at fault too. Perhaps, if an accident had occurred, we would have been liable.
The two things you need to do to emerge safely from a situation like this are, firstly, to be aware of what's going on around you. This specifically means what's going on behind you, and what's happening on the road you're trying to join. and secondly, you need to be travelling at an appropriate speed for the situation.
The first of these means good mirrorwork on approach, and early observations, backed up by further brief observations as you approach. Looking over your right shoulder can give a good idea of what's happening, and in a situation like this, the road you're joining is often not going to be covered by an ordinary look in your door mirror. There are a couple of problems with looking over your shoulder though. You're body twists around to the right, and this can cause you to turn the steering wheel to the right as well, which makes the car veer dangerously out of it's lane. Also, if you're looking over your shoulder, while driving forward, and something happens in front of you, well you're just going to smash straight into whatever it is, because you won't know it's happened.
The highway code recommends a glance over your shoulder as you approach the road you want to join.
Your door mirror will not really tell you what's going on on the road you're joining if you're sat back in your seat. If you lean forward in your seat, you get a wider field of view, and you still have some awareness, through peripheral vision, of what's going on ahead of you. Because you lean forward but your body is straight, the steering isn't affected as much.
If you're joining traffic that's travelling at speed, you also need to be travelling at speed if possible. If you're attempting to join a stream of traffic that's moving at 70 miles per hour, and you're doing only 30 miles per hour, you're allowing cars to close with you at a relative speed of 40 miles per hour. If you're doing 70 miles per hour as you join, then the gap you're moving into moves with you.
Ultimately, what happened today was my fault. My pupil is at test standard. He's not a learner except in the sense that all of us are. I'd assumed he'd be able to deal with the situation comfortably, so I didn't brief him about it beforehand.
Live and learn.