As much as it pains me to say it (I like driving fast), reducing the speed limit to 50mph both ways between J13 and J9 with average speed checks may be a good idea - it's a risky piece of road with constant last minute lane changes by cars and lorries alike, spontaneous queues forming and disappearing in seconds, and drivers failing to anticipate all of these in advance. Reducing the speed would at least give drivers more time to react, force them to set up their manoeuvres safely and in good time, and with any luck reduce the number of fender-benders resulting from those queues. That corner near Stockport with a similar setup feels safe as a result... why not do it at Barton too?