new seatbelt[MAX_PLAYERS];
public OnVehicleDamageStatusUpdate(vehicleid, playerid)
{
    if(seatbelt[playerid] == 0)
    {
        SetPlayerHealth(playerid,20);
        SendClientMessage(playerid,-1,"wear a seatbelt!! /belt");
     }
    return 1;
}
CMD:belt(playerid,params[])
{
    if(seatbelt[playerid] == 1)
    {
        seatbelt[playerid] = 0;
        SendClientMessage(playerid,-1,"Seatbelt off");
    }
    else if(seatbelt[playerid] == 0)
    {
        seatbelt[playerid] = 1;
        SendClientMessage(playerid,-1,"Seatbelt on");
    }
    return 1;
}