The complete iPACENOTES glossary of terms

15.08.2016. / Knowledge

In the previous blogs we've described two fundamental concepts behind any rally pace notes system: the way that corners' grades are measured (i.e. what exactly means L3) and how the racing line is determined based on a sequence of corner descriptions.

Once more, the goal of any pacenotes system is to provide driver minimal but sufficient set of information which allows him or her to drive through every corner at maximal possible speed. Pacenotes implicitly or explicitly describe optimal racing line, braking points, acceleration points, hazards and deviations from optimal racing line, jumps etc. For an experienced driver, pacenotes provide a way to almost visualize a great deal of a road in front of the car.

Besides plain corner curvature (or grade), pacenotes need to provide quite some number of other important information about the track. For example, not all L3 corners are equal; some of them are shorter, some are longer but their curvature is the same. The information whether the corner is short or long influences acceleration point (i.e. whether driver should go hard on throttle early or latter). Corners may also tighten or open, which means that their curvature changes as the corner progresses. Moreover, there may be various types of crests where typically road beyond the crest is not visible to the driver for some period. Pacenotes must also provide enough information to the driver what happens after the crest, where to put the car before the crest etc.

iPACENOTES aims to be an automated pacenotes system and for that reason the dictionary of all allowed words or descriptions which iPACENOTES will use must be fixed. In other words, we must select in advance the complete set of signs, words and notes which will be used in iPACENOTES. This is quite tricky, since in reality rally drivers use different concepts and words to describe the same road conditions or geometry.

We've interviewed several top rally drivers in order to understand the differences between their pacenotes. We've also analyzed lots of professional WRC on-board camera videos which gave us insight into differences among WRC drivers' pacenotes. At the end, our own research confirmed that the existing Jemba Inertia Notes System provides the most common denominator of all pacenotes systems which we have analyzed.

The Jemba Inertia Notes System is a computer software program used in rallying that automatically prints out stage notes for competitors to use. The purpose of the system is to allow organizers to create a consistent set of pace notes for all the competitors without having them to take additional time and resources to do the reconnaissance themselves. Currently, the system is used most heavily in the Rally America National Championship but is also used greatly for national championships in Canada, Sweden, Norway, New Zealand, and Great Britain (from Wikipedia). See also Jemba company home page.

An interesting software project which also greatly influenced our choice of pace notes vocabulary is Co-driver for Assetto Corsa racing simulation. Basically, this project provides automatic pacenotes generation for race tracks in Assetto Corsa racing simulation and, on the top of that, during the race it provides virtual co-driver which speaks out generated instructions.

It is worth noting that Jemba Inertia Notes System also provides virtual co-driver for notes recorded on an actual rally stage. Co-driver for Assetto Corsa and Jemba are therefore doing the same job: Jemba for real tracks and Co-driver for Assetto Corsa for tracks in racing simulation. iPACENOTES within that context provides another implementation of the same idea, but with one big difference. Jemba uses somewhat expensive equipment to record pacenotes for real roads; it requires a PC connected to the car's odometer and accelerometer (effectivelly, it requires connection to the car's CAN bus, typically by using OBDII connector). Co-driver for Assetto Corsa on the other hand collects the same information by using data available from the computer simulation of the track. iPACENOTES wants to achieve the same goal, but without using any expensive equipment - a plain smartphone or tablet should be sufficient.

So, here it is, the complete iPACENOTES glossary of terms:


L or R left or right corner
1 through 7 corner grade according to the iPACENOTES wheel scale
< (opens) a corner where the ending takes place very gradually
> (tightens) a corner where the curvature increases or tightens as the corner progresses; the level that it tightens to is specified, as in "R4 > 5"
short a corner that is shorter than a normal corner of the same curvature
lg (long) a corner longer than normal, but with the same radius
vlg (very long) a corner even longer than lg, but with the same radius
xlg (extra long) a corner even longer than vlg, but with the same radius
late a corner where the tightest curvature occurs late in the corner (tightens late in the corner)


Distance is the distance of flat road, in meters, between the ending of the previous turn and the beginning of the announced turn. When a turn goes immediately into another one, the distance reading is omitted, it is replaced by:

into if the distance is less than 5 meters
for if the distance is less than 15 meters
and if the distance is less than 30 meters


! (caution) characteristic of the road that requires care to negotiate - it may be deceptive, or rough, or difficult to maneuver at speed. It may cause you to damage your car or go off the road if not negotiated correctly
brake a caution that specifically references the need for a drop in speed (such as from a straightaway into a tight corner such as a L5)
keep in, keep out a recommendation for positioning the car in a corner either "in" - closer to the apex, or "out" - toward the outside of the corner, to avoid something such as ruts or a puddle
stay L or R a recommendation for positioning the car over a crest or jump in order to position the car correctly for the next corner or feature; also, at a Y intersection, take the left or right fork


/ (over) indicates that the corner spans over the crest, as in "R3/cr "
smCr (small crest) a small crest is either:
A: a crest where the road beyond the crest is not visible to the driver for some period (usually just before the crest)
B: a crest where the driver can see the road beyond it but the road immediately over the crest is hidden from view
cr (crest) a crest where the road beyond the crest is never visible to the driver prior to reaching the crest
bigCr (big crest) a crest where the road either rises up sharply into the crest or falls away sharply after the crest
lgCr (long crest) a crest of longer length than normal
smJmp (small jump) a feature where you can expect the car to get light on the suspension or possibly airborne
jmp (jump) a feature where you can expect the car to get very light on the suspension but it is more likely to get airborne


dip a place where the road undulates down and then up quickly in a U shape
wash a dip where the stage road crosses a stream bed; the bottom may be loose or bumpy
loose loose footing (as in gravel)
bump a bump is where there is a feature (such as an imbedded rock or a hard mound of dirt) that will cause the car to jerk up
rock a single imbedded rock you may be able to avoid or clear


o.c. off camber
n.c. don't cut; there is something hazardous on the inside of the corner
down the road descends significantly enough to affect braking and handling
nar (narrows) the road narrows enough to possibly affect your line
deceptive a feature that may look different than it really is

The above tables contain altogether around 30 different abbreviations (or words) which iPACENOTES will use. An example would be:

R4lg into ! L4/bigCr for R3 o.c. 150

which reads as "right four long into caution left four over big crest for right three off camber 150".

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