Horizontal curves have been recognised as a significant safety issue for many years, a more important factor than road width, vertical clearance or sight distance. This study investigates the issue of speed selection through curves from several different perspectives. The relationship between safety and curve speed in New Zealand was analysed using data from the Ministry of Transport’s Crash Analysis System (CAS) database. A sample of curves was selected and surveyed. Following this, a method for determining the appropriate safe curve speed for different vehicles was developed based on the vehicle performance characteristics. In parallel, a driving simulator was used to investigate the effect of different warning sign and road marking treatments on drivers’ curve speed selection and lateral positioning.