The Westlink was built as a fully tolled, gateless motorway employing electronic payment, with an initial toll-free period that ended on 15 January 2006. The toll was originally 29.91 cents per kilometre, capped after 20 kilometres (12 mi) at $5.98. On 1 April 2006, this increased to 30.07 cents per kilometre, capped after 20 kilometres (12 mi) at $6.01. As of 2015, the toll was 38.31 cents per kilometre, capped at $7.66, and adjusted quarterly according to the CPI.