1. Walk where possible on the side of the road facing the oncoming traffic. This might give a moment of advanced warning and a chance of getting out the way. Though this would have been unhelpful advice for people walking to the south of the river (actually the east) yesterday as it would have put them in the line of attack, but at least you could jump into the river.
2. Before crossing the road try to stand a little back from the edge and if possible behind an item such as railing, traffic light, lamp post etc to gain protection against the 'glancing blow' technique which will doubtless be developed in the coming years, and against buses right now of course which have bits that tend to sweep over the line of the kerb.
3. When crossing, do the prudent thing and get some other people between you and the possible line of attack. They might not do much, but any bit of velocity they might shave off can only help. What do you mean, cowardly? These are survival tips, not a guide to winning a George Cross.
4. Try to jump over the oncoming vehicle. This might not be straight-forward for non-gymnasts, and no use against buses and lorries, but surely worth a go against cars for the sport of the thing. Maybe a leap onto the bonnet then quick step and flying tuck, forward roll and pike.
5. Be, as we are constantly told, vigilant. What this means is to phone 999 every time our suspicion is aroused by anything. This will in no way clog up the phone lines, waste the time of the police and damage the likelihood of prevention of actual attacks.
What about dropping to the floor with arms and legs together (ideally with feet facing towards the car) when the vehicle is around 2 meters away? If they are going at speed then I would think they'd struggle to adjust course in sufficient time to get one of the tyres to roll over you. And actually, you are far more likely to survive a tyre rolling over you than you are being smashed by the front of the car.
On first reading I thought that sounded a bad idea, as most vehicles do not have the ride height to allow a person of average build beneath. A short trip up and down the road confirms that almost every car has a bumper too close to the ground - never mind the bits of dangling plumbing further under. Might work for some lorries. Would take some balls to try it though.
Well, in the case of a Hyundai i40 which was yesterday's weapon of choice, I think you could just about squeeze under. Sure, some of the trim may issue you a glancing blow but you wouldn't be taking the whole force. If jumping in the Thames was an option, I would take that first. However, this could work as a last resort. Perhaps consider adding an addendum to your guide?