This chapter explores what kinds of 'problems' congestion pricing and driver information systems can 'fix'. The impact and appropriateness of congestion pricing and driver information systems depend on both who is travelling and why they are travelling. In particular, driver information systems should be used to correct problems associated with incomplete information and congestion pricing systems should be used to correct externalities. The only way a driver information system could be used to get people to change their routes is to tell them that another route costs less. There are many different ways to implement driver information systems. First, driver information systems can vary in the nature of the information they provide. Second, the spatial structure of driver information systems can vary in important ways. Third, different driver information systems can have different temporal structures.