location /mytraffic {
            traffic_statistics request_times packet_bytes status_codes;
        }

        location /mytraffic1 {
            traffic_statistics request_times;
        }

        location /mytraffic2 {
            traffic_statistics packet_bytes;
        }

        location /mytraffic3 {
            traffic_statistics status_codes;
        }

        log_by_lua_file /usr/local/nginx/lua/traffic/get_traffic_info.lua;
        location /mytraffic_lua {
            default_type "text/html";
            content_by_lua_file /usr/local/nginx/lua/traffic/show_traffic_info.lua;
        }

http://blog.sina.com.cn/s/blog_15753dca00102w75h.html