Along with the efforts to cope with the increase of functions which require higher communication bandwidth in vehicle networks using CAN-FD and vehicle Ethernet protocols, we have to deal with the problems of both the increased busload and more stringent response time requirement issues based on the current CAN systems. The widely used CAN busload limit guideline in the early design stage of vehicle network development is basically intended for the further frame extensions. However in case of it is inevitable to increase the current busload design limit, we need to analysis the actual levels of the maximum frame response time delays and the differences with the estimation and measurement. To estimate the maximum frame latency at the design phase, since the current worst case response time analysis method is only providing the upper bounds, the efficient evaluation methods should be applied without using the control unit level information. In this context, to increase the accuracy of the response time estimation, we use the probability based distributed response time simulation method and compare it with the measured maximum response time results. To measure the maximum response time, a new burst based data analysis method is developed which uses only the measured receiving time of frames in a communication bus. As a result, by means of the improved methods that reduce the gap of estimation and measurement of timing behavior in a network, we can analysis the network system timing performance efficiently at the early phase of vehicle network developments.