Time, Speed, Distance. What it's all about.

We've established that the way to do well in a road rally is to score as few points as possible, and the way to achieve that is to be on time at the checkpoints. So just how does one go about being on time at the checkpoints time after time?
It all comes down to three little words. Time, Speed, and Distance or T,S,D.
Road Rallies can also be known as TSD rallies to emphasize the importance of these elements.
When you register at your road rally event, you will be given a set of instructions to follow the route of the rally. The instructions can vary from plain and simple written/pictoral instructions, called Tulips (that's a subject for another day) to some more complicated map plotting. What is common to all instructions is being able to work with two of the factors to produce the third. For example, if you know that the next junction to turn at is a mile away and you have 2 minutes to get there, it plain and simply obvious that you need to average 30 mph to reach the turn. This is the basic building block of road rallying. If you reach your marks on time, be they a road junction, landmark or checkpoint, then you'll be doing fine.
To do this consistently you need a system, and there are almost as many systems as there are Rally-ists. Many first timers, ourselves included, work it all out as they go along, doing the calculations as needed, and reading the times off a stopwatch. This is known as "seat of the pants" or SOP. Very experienced rally-ists can be as accurate using SOP methods as less experience competitors using expensive equipment. One of the most comprehensive systems out there was developed by Minnesota Rallyist Gary Starr and can be downloaded here.
 Don't trust your maths to give you accurate distance/time calculations? Then there are Rally Tables, (like this simplified version here),  available to purchase that have the calculations all done for you. Using the simple example linked to you can see that at 36 mph (on the left hand side) it will take 1.66666 minutes to travel one mile, five minutes to travel three miles etc;. Bought tables are much more comprehensive and can take some time to work with before the Rallye starts to work everything out.
Still daunted by all this? Then move into the 21st century and use your Smartphone, there are many Apps on the market to help the aspiring Rallyist that we can discuss later to help you. The Apps, of course, are limited by the GPS technology in the Smartphone. Not accurate enough for you? Not enough technology for you? Then you can get really serious and move up to expensive distance sensors running off the wheels or very hi-tec GPS measuring devices for greater accuracy. But all that is for another day.