You might not but...
Average speed probably not due either way to the numbers....
More to do with the lorry drivers that are being "overtaken" not easing off to let another lorry past - just sitting on their limiter because they can.......an ego thing... or just not concentrating on their driving...
Car/van/truck/any vehicle drivers not overtaking anyone but just sitting in the overtaking lanes oblivious to what's behind them or just don't want to be passed.."I'm here so you can wait" ... or just uneducated in how it should work.....
I now ( having "retired" lol!) drive trucks, vans, abnormal load escort vehicles nationally and internationally for a living (done thousands of miles on the A1 between Herts and the north east ffs) , and I drive cars for whatever everyday needs I have
It's really quite simple - keep to the left until overtaking, use your mirrors and indicators, be courteous, it will benefit everyone......
Don't need to get involved if some tw@t wants to get somewhere in a hurry - let them and the law enforcers deal with it - what comes around...
For me it appears to be a total lack of understanding and even training at the outset, the most important time on one's journey to being a driver....
And of course absolutely no one is perfect, we're all human and make mistakes and need to acknowledge that.
It will help, but not solve the A1's issues.....