Pacey's platoon dispersion model is based on the assumption that the speed of vehicles follows the normaldistribution spreading from the minus infinity to the positive infinity.However,this assumption cannot properly reflectthe actual traffic situation.In order to solve this problem,based on the field data,a more practical platoondispersion model is constructed under the assumption that the speed follows the truncated lognormal distribution rangingfrom the minimum speed to the free flow speed.Then,a piecewise function is developed to describe the platoondispersion as it moves to the downstream intersection and to reveal the relationship between the flow distributionmoving to the downstream intersection and that leaving the upstream intersection. Finally,by taking the signalcoordination control of an adjacent intersection as a case,the distribution mode of platoon flow is discussed accordingto the measured data,and the validity of the proposed model is verified by a comparison between the proposedmodel and the Robertson model.