Tracking Car Collisions

[hiran]

Hi, I'm doing a research in affective game based learning and I want to pool collisions (with surface, car to car, and with walls) to an external analyzer. After scanning through game.cpp I could locate the following methods,
UpdateCarChassisCollisions()
UpdateCarWheelCollisions(...)
UpdateCarWheelCollisionsWithSurfaces(...)
UpdateCarWheelCollisionsFromCached(...)
UpdateCarWheelCollisionsFromCachedWithSurfaces(...)

Next after some experiments I inserted my code segment as follows,

UpdateCarChassisCollisions() {
...
if (carcontrols_local.first == &car) isColChassis = true;
...}

UpdateCarWheelCollisions(...) {
...
if (carcontrols_local.first == &car) isOnTrack = true;
...}

UpdateCarWheelCollisionsWithSurfaces(...) {
...
if (carcontrols_local.first == &car) isColSurface = true;
...}

isOnTrack works perfectly and it gives whether the car is on the track or not. isColChassis gives about car to car and wall collisions, but doesn't work perfectly. No effect in isColSurface.
The purpose of the other two methods is unclear to me.

Someone please explain me how to get these collision information correctly.

Thanks in advance.