//above main()

new License[MAX_PLAYERS];

#define COLOR_GOLD 0xFFD700AA

//the check to see if they are a driver

public OnPlayerStateChange(playerid, newstate, oldstate)
{
    if(IsPlayerConnected(playerid) && newstate == PLAYER_STATE_DRIVER)
    {
 	TogglePlayerControllable(playerid,0);
   	SendClientMessage(playerid,COLOR_GOLD,"Checking for Drivers License");
     	SetTimer("LicenseCheck",2000,0);
    }
    return 1;
}

//license check

public LicenseCheck()
{
    for(new i = 0; i < MAX_PLAYERS; i++)
    {
	if(IsPlayerConnected(i) && License[i] == 1)
	{
	    TogglePlayerControllable(i,1);
	    SendClientMessage(i,COLOR_GOLD,"Drivers License Found! Please drive safely.");
	}
	else
	{
            TogglePlayerControllable(i,1);
	    SendClientMessage(i,COLOR_GOLD,"No Drivers License Found! You are not allowed to drive!");
            RemovePlayerFromVehicle(i);
	}
    }
}

//the command I used to test if the above code worked

if (strcmp(cmdtext, "/givelicense", true) == 0)
{
    if(IsPlayerConnected(playerid) && License[playerid] == 0)
    {
        License[playerid] = 1;
	SendClientMessage(playerid,COLOR_GOLD,"You now have an Drivers License!");
    }
    else
    {
        SendClientMessage(playerid,COLOR_GOLD,"You already have an Drivers License.");
    }
    return 1;
}