How to Add Traffic Sign in ALV report

REPORT  ZTRAFFICSIGN.

TYPE-POOLS: slis.  " SLIS contains all the ALV data types
*&---------------------------------------------------------------------*
*& Data Types
*&---------------------------------------------------------------------*
TYPES: BEGIN OF ty_sbook.
        INCLUDE STRUCTURE sbook.
TYPES: icon TYPE c,  " Add field to hold traffic light value
       END OF ty_sbook.
*&---------------------------------------------------------------------*
*& Data Declaration
*&---------------------------------------------------------------------*
DATA: it_sbook     TYPE TABLE OF ty_sbook.
DATA: wa_sbook     TYPE ty_sbook.
DATA: it_fieldcat  TYPE slis_t_fieldcat_alv,
      wa_fieldcat  TYPE slis_fieldcat_alv.
DATA: is_layout    TYPE slis_layout_alv.
DATA: g_repid      TYPE sy-repid.
*&---------------------------------------------------------------------*
*& START-OF-SELECTION
*&---------------------------------------------------------------------*
START-OF-SELECTION.
  g_repid = sy-repid.
*Fetch data from the database
  SELECT * UP TO 20 ROWS FROM sbook INTO TABLE it_sbook.

*Assign different traffic lights to each row based on condition
  LOOP AT it_sbook INTO wa_sbook.
    IF wa_sbook-luggweight LE 0.
      wa_sbook-icon = 1.  " Red Traffic Light
    ELSEIF wa_sbook-luggweight LE 10.
      wa_sbook-icon = 2.  " Yellow Traffic Light
    ELSE.
      wa_sbook-icon = 3.  " Green Traffic Light
    ENDIF.
    MODIFY it_sbook FROM wa_sbook TRANSPORTING icon.
    CLEAR: wa_sbook.
  ENDLOOP.

*Build field catalog
  wa_fieldcat-fieldname  = 'CARRID'.    " Fieldname in the data table
  wa_fieldcat-seltext_m  = 'Airline'.   " Column description in the output
  APPEND wa_fieldcat TO it_fieldcat.
  CLEAR wa_fieldcat.

  wa_fieldcat-fieldname  = 'CONNID'.
  wa_fieldcat-seltext_m  = 'Con. No.'.
  APPEND wa_fieldcat TO it_fieldcat.
  CLEAR wa_fieldcat.

  wa_fieldcat-fieldname  = 'FLDATE'.
  wa_fieldcat-seltext_m  = 'Date'.
  APPEND wa_fieldcat TO it_fieldcat.
  CLEAR wa_fieldcat.

  wa_fieldcat-fieldname  = 'BOOKID'.
  wa_fieldcat-seltext_m  = 'Book. ID'.
  APPEND wa_fieldcat TO it_fieldcat.
  CLEAR wa_fieldcat.

  wa_fieldcat-fieldname  = 'FORCURAM'.
  wa_fieldcat-seltext_m  = 'Price'.
  APPEND wa_fieldcat TO it_fieldcat.
  CLEAR wa_fieldcat.

  wa_fieldcat-fieldname  = 'FORCURKEY'.
  wa_fieldcat-seltext_m  = 'Currency'.
  APPEND wa_fieldcat TO it_fieldcat.
  CLEAR wa_fieldcat.

  wa_fieldcat-fieldname  = 'LUGGWEIGHT'.
  wa_fieldcat-seltext_m  = 'Weight'.
  APPEND wa_fieldcat TO it_fieldcat.
  CLEAR wa_fieldcat.

  wa_fieldcat-fieldname  = 'WUNIT'.
  wa_fieldcat-seltext_m  = 'Unit'.
  APPEND wa_fieldcat TO it_fieldcat.
  CLEAR wa_fieldcat.

*Fill layout info.
*Fill traffic lights field name in the ALV layout
  is_layout-lights_fieldname = 'ICON'.

*Pass data and field catalog to ALV function module to display ALV list
  CALL FUNCTION 'REUSE_ALV_GRID_DISPLAY'
    EXPORTING
      i_callback_program = g_repid
      is_layout          = is_layout
      it_fieldcat        = it_fieldcat
    TABLES
      t_outtab           = it_sbook
    EXCEPTIONS
      program_error      = 1
      OTHERS             = 2.

OUTPUT