1. Highway statistics 2016; 2018. https://www.fhwa.dot.gov/policyinformation/statistics/2016/hm260.cfm. [accessed 10 May 2018].
2. Road Network 2017; 2018. http://erf.be/statistics/road-network-2017/. [accessed 10 May 2018].
3. 2017 Statistical bulletin of the development of the transportation industry; 2018. http://zizhan.mot.gov.cn/zfxxgk/bnssj/zhghs/201803/t20180329_3005087.html. [accessed 10 May 2018].
4. Energy harvesting technologies in roadway and bridge for different applications-A comprehensive review;Wang;Appl Energ,2018
5. Energy harvesting on road pavements: state of the art;Duarte;Proc Inst Civil Eng,2016