We examine various realistic generalizations of the basic cellular automaton model describing traffic flow along a highway. In particular, we introduce a slow-to-start rule which simulates a possible delay before a car pulls away from being stationary. Having discussed the case of a bare highway, we then consider the presence of a junction. We study the effects of acceleration, disorder, and slow-to-start behaviour on the queue length at the entrance to the highway. Interestingly, the junction's efficiency is improved by introducing disorder along the highway, and by imposing a speed limit.