function traffic 

umax = 1;       % max speed
rhomax = 1;     % max density
tmax = 4;      % finale time
L = 10;         % length of road

N = 500;        %number of cells
dx = L/N;       % cell size
x = dx*(0:N);     % nodes

dt = dx/2;          % time step
M = ceil(tmax/dt);        % number of time steps
t = dt*(0:M);           % time vector

u = zeros(M+1,N+1);     % array to store solution

u(1,:) = u0(x);     % intialization
u(:,1) = u0(x(1));
u(:,N+1) = u0(x(N+1));  % sloppy boundary fix

for j = 1:M
%    u(j+1,2:N) = COMPLETE THIS!!!!
end

% mesh(x,t,u)
% xlabel('x','FontSize',15)
% ylabel('t','FontSize',15)
% zlabel('density','FontSize',15)

contourf(x,t,u)
xlabel('x','FontSize',15)
ylabel('t','FontSize',15)
colorbar

function f = f(u)
f = u.*(1-u);

function u0 = u0(x)
u0 = 0*ones(size(x));
k = find(x>1& x <4);
u0(k) = .5;

k = find(x>4&x<5);
u0(k) = 1;