Houses, roads, drains and other infrastructure.
Traffic engineering is a sub-set of transportation engineering. Traffic specifically refers to the movement of people and vehicles, usually through roads and highways. Traffic engineers modify the technical aspects of road design to maximise traffic flow and reduce congestion. Road geometry, traffic lights, road signs and pedestrian walkways are all related and optimized to achieve one common goal; reducing traffic congestion in a safe manner. Skills used on a daily basis by traffic engineers include data analysis problem solving skills when assessing traffic and accident reports.