Generally, transportation infrastructure is very good and continues to be improved, mainly in the west side of the island. Many infrastructure improvements are currently being pursued, such as the first rapid transit lines opening in Kaohsiung in 2008 and a doubling in size of Taipei's rapid transit system by 2013 now underway; the country's highways are very highly developed and in good maintenance and continue to be expanded, especially on the less developed and less populated east coast, and a controversial electronic toll system has recently been implemented.