  Strange nonchaotic attractors (SNA) arise in quasiperiodically driven systems
in the neighborhood of a saddle node bifurcation whereby a strange attractor is
replaced by a periodic (torus) attractor. This transition is accompanied by
Type-I intermittency. The largest nontrivial Lyapunov exponent $\Lambda$ is a
good order-parameter for this route from chaos to SNA to periodic motion: the
signature is distinctive and unlike that for other routes to SNA. In
particular, $\Lambda$ changes sharply at the SNA to torus transition, as does
the distribution of finite-time or N--step Lyapunov exponents, P(\Lambda_N).
