A professional who conducts field studies to determine traffic volume, speed, effectiveness of signals, adequacy of lighting, and other factors influencing traffic conditions. Responsibilities include:

• Analyzes traffic volume and interviews motorists at assigned intersections or other areas where congestion exists or where disproportionate number of accidents have occurred (traffic checker).
• Determines average speed of vehicles, using electrical timing devices or radar equipment.
• Times stoplight or other delays, using stopwatch.
• Observes lighting, visibility of signs and pavement markings, location of traffic signals, width of street or roadway, and other considerations affecting traffic conditions.
• Draws graphs, charts, diagrams, and similar aids to illustrate observations and conclusions.
• Computes mathematical factors for adjusting timing of traffic signals, speed restrictions, and related data, using standard formulas.
• Prepares drawings of proposed signal installations or other control devices, using drafting instruments.
• May prepare statistical studies of traffic conditions.
• May recommend changes in traffic control devices and regulations on basis of findings.