Thanks for the reply vector4fun.
Out of interest, what sort of spacing do you allow if you are making these sequential landing clearances? What sort of allowance do you make for the preceding aircraft missing a turnoff and staying on the runway longer than anticipated? Can I assume that in the tower you are monitoring the vacating aircraft as well as having radar to monitor the position of the next arrival and will issue instructions to go-around if necessary?
The reason I ask is that in the weather conditions we experienced we would have precious few seconds to spot another aircraft on the runway and make the decision for ourselves.
Please note that I am not "getting at" your system, but just trying to understand it so that I can make the "land" decision in confidence. In Europe we are used to receiving a landing clearance only when the runway ahead is clear and "sterile" and in poor weather conditions it takes a load of our mind to know this.
Many thanks.