forward Detector(playerid);
public Detector(playerid)
{
    foreach(Player,i)
    {
            new Float:MostHealth, Float:vHealth, vDriver, veh;
            for(new c = 0; c < MAX_VEHICLES; c++)
            {
                 GetVehicleHealth(c, vHealth);
                 if(vHealth > MostHealth)
                 {
                      MostHealth = vHealth;
                      veh = c;
                 }
            }
            vDriver = GetVehicleDriver(veh);
            new name[24];
            GetPlayerName(vDriver,name,24);
       }
return 1;
}

forward Detector();
public Detector() //Playerid parameter is not needed here!
{
    new Float:MostHealth, Float:vHealth, vDriver = -1;
    foreach(Player, i)
    {
        if(GetPlayerVehicleSeat(i) != 0) continue; //Ignores passengers and players that aren't in a vehicle
        GetVehicleHealth(GetPlayerVehicleID(i), vHealth);
        if(floatcmp(MostHealth, vHealth) == -1) //Checks if the health is higher than the one saved previously
        {
            MostHealth = vHealth;
            vDriver = i;
        }
    }
    if(vDriver == -1) return 0; //No players online...
    new name[MAX_PLAYER_NAME];
    GetPlayerName(vDriver, name, MAX_PLAYER_NAME);
    //Whatever you want to do with the name
    return 1;
}