History of engineering and technology 15 Technology: general issues 12 Highway & traffic engineering 9 History of engineering & technology 6 Traffic congestion 6 Transportation 6 Highway and traffic engineering 4 Intelligent systems 4 Machine learning 4 Research & information: general 4 Roads and streets 4 Smart city 4 Street traffic control 4 TA Engineering (General). Civil engineering (General) 4 Traffic signals 4 Transport planning & policy 4 Vehicles 4 Accidents 3 Adaptive traffic management system 3 Advanced traffic management systems 3 Automation 3 Built environment 3 City & town planning - architectural aspects 3 DBSCAN method 3 Design and implementations 3 Developing countries 3 Energy technology & engineering 3 Highway administration 3 Highway planning 3 Highway traffic control 3