Bush taxis, generally beaten-up old vehicles, cover outlying communities that large buses don't serve but also run between major towns and cities. There is sometimes a surcharge for luggage. Most leave from the gares routières; morning is the best time to find them.
The omnipresence of zems (zemi-johns; motorbike taxis) has translated into the near disappearance of car taxis for short journeys. While they are by far the fastest and most convenient way of getting around, they are dangerous: most drive like lunatics and helmets are not available.
Zem drivers wear numbered yellow shirts in Cotonou (various colours in other towns). Hail them just as you would a taxi, and be sure to agree on a price before the journey. The typical fare costs from CFA150 to CFA250 for trips within a town. They are also an easy way to get to remote villages where public transport is infrequent.