[Konstantinos]

If I were you, then I'd check the closest vehicle of a player:

pawn Код:

new
    vehicleid = GetClosestVehicle(playerid);

if (vehicleid != INVALID_VEHICLE_ID)
{
    // "vehicleid" stores the closest vehicle's ID.
}

pawn Код:

stock GetClosestVehicle(playerid) 
{
    new
        vehicleid;
    
    if ((vehicleid = GetPlayerVehicleID(playerid))) return vehicleid;

    new
        Float: px,
        Float: py,
        Float: pz,
        Float: distance = 999.0,
        Float: tmp;
    
    vehicleid = INVALID_VEHICLE_ID;
    GetPlayerPos(playerid, px, py, pz);
    for (new v = 1; v != MAX_VEHICLES; ++v)
    {
        if ((tmp = GetVehicleDistanceFromPoint(v, px, py, pz)) < distance) 
        {
            distance = tmp;
            vehicleid = v;
        }
    }
    return vehicleid;
}