by Technomad » Fri Mar 29, 2013 4:37 pm
Been following this thread on Pistoheads as well, so been dissecting how I approach a potential multi-vehicle overtake: when they arise, I'm trying to take into account:
- My commit distance - in other words, where's my next check point for continuing the manoeuvre? It may be 2, 3, 5 vehicles down the line - wherever there's a point where I could drop back in without causing others to take avoiding action. Obviously the longer the commit distance, the longer a sight line you need at any given speed. So I'm not committing without a check point being visible.
- my ability to react to someone pulling out.
- the sight line as it exists at the start of the overtake and as it develops during the overtake
- the assumed ability to perceive and react of the drivers I'm overtaking. This is particularly true on a bike - most car drivers simply cannot conceive of a bike's ability to accelerate and therefore don't factor it in. However it's also true of high performance cars.
- My likely terminal velocity at the end of the manoeuvre - I may be able to complete the manoeuvre safely only by using so much power that I then have to immediately scrub off 40-50mph. Embarrassing at best…
- plus of course all the usual stuff for a single vehicle overtake...
So throttle use then becomes a function of all of the above, factored by the vehicle I'm driving: If I'm in my diesel 4x4 I may well use full throttle at first, to minimise TED., remembering that my overtaking ambition is much more limited than in my other vehicles. In my 911 or on a bike, I'd say that if I HAVE to use full throttle to complete an overtake, I'm probably pushing my luck on a public road - in a multi-vehicle overtake, full throttle for more than a second or two would have me straight into custodial sentence territory and certainly violating conditions 2 and 4 above. Where that extra power does help is when acceleration helps you get out of a developing situation (for instance, seeing the person you're overtaking start to pull out when you're fully alongside).
When I reach an intermediate check point, if I do have to drop it, I'll always try to match speed before pulling in, rather than dive in and slam on the brakes. Of course, that then gives Mr Angry Numpty a chance to try to deliberately close the gap and prevent me completing the manoeuvre - something else to watch for.