Urban Network Operations

Urban Traffic Control Centres (TCCs) have operated traffic signal systems for years using a wide range of software packages. Their main purpose is to keep traffic moving in the urban network of arterial roads. As more ITS devices are being deployed in the arterial networks, the use of ITS for Arterial Traffic Management Systems (ATMS) is becoming commonplace. European practice is to refer to Urban Traffic Control (UTC), or Urban Traffic Management and Control (UTMC).

A summary of operations for a TCC that controls an urban arterial road network is given in the tables below. (See also TCC Functions)

All Traffic Conditions

	Operational Function
Surveillance	Visual monitoring	CCTV, video wall, work-stations, video “tours”	Maximum visual coverage of network
	Sensor monitoring	Electronic detectors	Maximum sensor coverage of network, capture traffic characteristics
	Vehicle probes	Mobile safety patrols, crowd sourcing, floating vehicles	Detect and verify incidents in timely fashion
Traffic control/ influence	Signal operation	Traffic signal controllers	Regulate traffic flow through intersections, along corridors and in networks
	Traveller information	VMS and signals, PDMS, HAR, 511, media feed	Inform public and logistics managers of conditions for self-decisions

Recurring Congestion

Operational Function	Operational Method	Resources Used	Desired Result
Traffic control/ influence	Signal operation	Traffic signal controllers and traffic control software	Regulate traffic flow particularly along corridors and through networks
	Contra-flow or other special lane use	Lane signals, VMS	Increase roadway capacity

Weather Events

Operational Function	Operational Method	Resources Used	Desired Result
Surveillance	Sensor monitoring	RWMS (although rare on arteries)	Detect adverse weather
	Visual monitoring	CCTV, video wall, workstations, video “tours”	Detect and verify adverse weather

Traffic Incidents

Operational Function	Operational Method	Resources Used	Desired Result
Surveillance	Visual monitoring	CCTV, video wall, workstations, video “tours”	Detect and verify incident, dispatch response, notify other responders
	Incident notification	Police, Emergency Control Centres	Initiate response
	Vehicle probes	Safety service patrol (if used)	Detect incidents, SSP respond and assist
Signal operation	Adaptive signal controllers	Regulate traffic flow around incident	Improve throughput
	Traveller information	VMS, PDMS, HAR, 511, website, media feed, social media	Encourage diversions and journey time changes

Work Zone and Maintenance activities

Operational Function	Operational Method	Resources Used	Desired Result
Traffic control/ influence	Traveller information	VMS, PDMS, HAR, 511, website, media feed, social media	Safe, free flow past maintenance and other road work or diversion of route

Key to Resources

Resource	Technology	Further information
511 (USA)	Telephone travel information system	Pre-trip Information
CCTV	Closed-circuit Television	CCTV
eCall	Automated vehicle collision reporting system	Warning Systems
Electronic detectors	Vehicle and pedestrian sensors	Roadway Sensors
HAR	Highway Advisory Radio	Radio
Lane signals	Overhead VMS showing lane availability	Highway Traffic
Media feed	Automatic feed of information to websites, radio and TV stations	Pre-trip Information
PDMS	Portable Dynamic Message Sign	User Interfaces
Queue detectors	Electronic sensors to detect queues / queue length	Vehicle Detection
Ramp signals	Traffic signals to control traffic volumes entering a motorway / freeway	Highway Traffic
RWMS	Road Weather Management Systems	Weather Monitoring
Social media	Facebook, Twitter, etc	Social Media & Data
Speed advisory VMS	Advisory Variable Message Signs	Use of VMS
Speed limit VMS	Mandatory Variable Message Signs	Use of VMS
Video “tours”	Successive display of CCTV images from different cameras	Traffic Control
Video wall	Wall-mounted screens to display CCTV images	Traffic Control
VMS	Variable Message Signs	Use of VMS