Research conclusions:By comparing these three sets of theories (Zhao Liping's theory of Chang'an University, He Yulong and Sun Xiaoduan's theory of Beijing University of Technology and interchange accelerating and decelerating sections length theory in road specification)，the following conclusion is found:(1)Chang'an University and Beijing University of Technology only gives the calculated value for decelerating section of speed limit zone，not calculated for accelerating section，there should be also the accelerating transition section between the speed limit zones.(2)The length of the transition section speed limit zone is recommended to use the value derived by interchange accelerating and decelerating sections length in road specification.(3)In highway and urban road，in the accelerating transition section of downhill section and the decelerating transition section of uphill section，when the longitudinal slope is greater than 2%，its length should be amended. (4)The research results can be used for highway and urban road speed management.