The exact solutions of differential equation with delay
  The exact solutions of the first order differential equation with delay are derived. The equation has been introduced as a model of traffic flow. The solution describes the traveling cluster of jam, which is characterized by Jacobi's elliptic function. We also obtain the family of solutions of such type of equations. 
K. Hasebe (Aichi U.), A. Nakayama (Gifu Keizai U.), Y. Sugiyama (City   C. of Mie)