[HaiderABbas]

I want something which detects players car falls from the map or falls in water ,

[SMW]

when vehicle falls into water its automatically called OnVehicleDeath

[HaiderABbas]

and if anyone falls from the derby map ?

[Vince]

Create a timer to check their position. If their Z height is below a certain point then you can deduct that they've fallen off the map. Say, if your map is at Z height 100 then you can deduct that they fell off if their Z height is 90 or lower.

[ivanVU]

You can check player Z coordinate.

new Float:Pos[3];
GetPlayerPos(playerid, Pos[0], Pos[1], Pos[2]);

if(!IsPlayerInRangeOfPoint(playerid, 20.0, x coord, y coord, z coord)) // derby map coord, Z is important!
{
// what to do if player is not in derby map
}

[HaiderABbas]

and derby map is not a straight line , it map is up and down , one side another down , its not a road :/ so