The concept of an individual red carpet seems to me to be a tremendous waste of material, however, especially if the dignitary in question can't park his car properly. He might end up at an angle, for example, five feet or more from the kerb. Maybe standard issue red carpet comes supplied with an extra ten feet or so to allow for this kind of thing. Whatever, there ought to be a more efficient solution.
An obvious one, of course, is simply to glue a couple of red carpet tiles to the dignitaries' shoes for the duration of the event. Unfortunately, there are a few drawbacks to this. Because red carpet tiles are readily available in any DIY store, anyone could glue them to his feet and pretend to be someone exalted. Then, before you knew it, you'd have complete nobodies walking into, say, new art galleries or supermarkets and declaring them open. Or worse, a red carpet tile-equipped nobody could travel to Moscow and conclude a nuclear disarmament treaty with Vladimir Putin, thus leaving the UK effectively defenceless in the face of a renascent, increasingly bellicose Russia.
In my opinion, top hotels, theatres, ministries, and so on, ought to supply individual stiffened loops of red carpet, about 16 feet or so in circumference. Then, on State occasions, doormen could wheel them out to the dignitaries' cars and invite them to step inside and start walking. Thus the VIPs could go any distance they desired, confident that there would always be red carpet beneath their feet. Navigation might be a problem, as the VIPs wouldn't be able to see where they were going. However, it could be overcome by the doormen giving directions: "Left a bit, Your Majesty. Mind the lamp post. That's it. Over the kerb, now. Watch out for the dog turd on your far left." And so on.
On the other hand, it could cause a bit of trouble. For instance, a king might assume he had automatic right of way over a president. For his part, the president might think that, seeing as he's an elected representative of the people rather than being a mere hereditary head of state, his loop of red carpet should be given precedence. Another European war could result, infinitely more terrible than the First and Second.