Question 1 of 5: The Definition of ITS, the National Architecture Interface, and the User-Service Bundles

Question 1: The Definition of ITS, the National Architecture Interface, and the User-Service Bundles (20 points)

Question text not reproduced: the examination questions are © Engineers and Geoscientists BC. Open the official past paper (linked at the top of this page) to read the question, then follow the worked solution below.

(a) Definition of ITS (2 points)

Intelligent Transportation Systems are the coordinated application of sensing, information, communication, computing and control technologies to the transportation system — to its infrastructure, its vehicles, its operators and its travellers — in order to improve the safety, efficiency, reliability, productivity and environmental performance of that system. The defining characteristic, and the one worth stating explicitly in an answer, is that ITS buys performance from information rather than from concrete: it extracts more service from a fixed physical network by knowing more about the network's state, by acting on that knowledge in real time, and by telling travellers what they need in order to make better choices. ITS is therefore not a class of hardware but an integration discipline; the individual detectors, controllers, radios and screens are unremarkable, and it is the architecture that binds them into a system that constitutes the intelligence.

(a) The National ITS Architecture Interface and its application areas (8 points)

The U.S. National ITS Architecture is a common framework for planning, defining and integrating ITS. It is deliberately not a design and specifies no product: it fixes what functions exist, which entity performs each of them, and above all what information must pass between them, and it leaves the choice of technology to the deploying agency. Its physical view assigns every ITS element to one of about twenty-two subsystems, and those subsystems fall into four classes. Centres are the fixed management functions — traffic management, transit management, emergency management, toll administration, commercial vehicle administration, fleet and freight management, information service provider, archived data management, maintenance and construction management. Field subsystems are the equipment distributed along the roadside: the roadway subsystem, parking management, toll collection, commercial vehicle check and security monitoring. Vehicles comprise the basic driver vehicle plus its four specialisations — transit, commercial, emergency and maintenance and construction vehicles. Travellers comprise personal information access devices and remote traveller support such as a kiosk or a station display.

What the question calls the Architecture Interface is the set of communication interface classes that join these four subsystem classes, and the architecture defines exactly four of them. They are the load-bearing part of the whole framework, because it is the interfaces, not the boxes, that determine whether independently procured systems will in fact interoperate.

The first class is fixed-point to fixed-point, the wireline interface. It carries centre-to-centre exchange between peer management centres — traffic management to emergency management, one municipality's centre to the neighbouring region's — and centre-to-field communication from a centre out to the roadside equipment it controls. In practice it runs on agency-owned fibre, leased circuits or an IP network, and the standards that ride on it are TMDD for centre-to-centre and the NTCIP suite for centre-to-field. Its application areas are traffic management and signal control, incident and emergency coordination, transit dispatch, toll and fare administration, work-zone management, archived data, and every form of inter-agency resource sharing.

The second class is wide-area wireless, in both its one-way broadcast form (highway advisory radio, subcarrier and satellite data broadcast) and its two-way form (the commercial cellular network). It is the interface between the centres and the travelling public wherever the public happens to be, so its application areas are pre-trip and en-route traveller information, route guidance, mayday and emergency notification, personal security, transit vehicle location reporting, and commercial fleet and freight management.

The third class is short-range wireless between the field and a passing vehicle, historically Dedicated Short-Range Communications in the 5.9 GHz band and now equally cellular vehicle-to-everything. It is characterised by very low latency over a range of a few hundred metres, which is what makes it the only interface suitable for anything safety-critical or transaction-based at speed. Its application areas are electronic toll and fare payment, commercial vehicle electronic clearance and roadside screening, transit signal priority and emergency vehicle pre-emption, and the infrastructure-to-vehicle safety applications: red-light violation warning, curve speed warning, work-zone warning and signal phase and timing broadcast.

The fourth class is vehicle-to-vehicle, an ad hoc wireless interface with no infrastructure in the path at all. Its application areas are entirely in the safety and automation domain: forward collision warning, emergency electronic brake lights, blind-spot and lane-change warning, intersection movement assist, do-not-pass warning, and the cooperative platooning and automated operation applications that build on them.

Taken together, the applications these interfaces serve are grouped by the current architecture into a dozen application or service areas: traffic management, traveller information, public transportation, commercial vehicle operations, public safety and emergency management, parking management, maintenance and construction, road weather, vehicle safety, sustainable travel and demand management, electronic payment and pricing, and the cross-cutting data management and support services. In Canada the same four subsystem classes and the same four interface classes are carried into the ITS Architecture for Canada, and a municipality that intends to draw on federal or provincial ITS funding is normally required to demonstrate that its project conforms to a regional architecture derived from it.

(b) User-service bundles and their user services (10 points)

User services are the architecture's statement of what ITS does for somebody — expressed from the point of view of the traveller, the operator or the agency rather than of the equipment — and they are the starting point of any ITS plan, because the regional architecture is built by selecting the user services a region wants and then tracing the subsystems and interfaces they imply. The most current version that uses this vocabulary is National ITS Architecture version 7.1 of January 2012, which defines thirty-three user services grouped into eight user-service bundles. The list is reproduced in full below.

The Travel and Traffic Management bundle is the largest, with ten services: pre-trip travel information; en-route driver information; route guidance; ride matching and reservation; traveller services information; traffic control; incident management; travel demand management; emissions testing and mitigation; and highway-rail intersection. It contains both halves of the surface-street business — informing the traveller and controlling the network — which is why Questions 3 and 4 of this paper, on ATMS and ATIS, both draw from it.

Public Transportation Management holds four services: public transportation management, en-route transit information, personalised public transit, and public travel security. Electronic Payment holds a single service, electronic payment services, which nonetheless underpins tolling, transit fare collection and parking charges alike. Commercial Vehicle Operations holds six: commercial vehicle electronic clearance; automated roadside safety inspection; on-board safety and security monitoring; commercial vehicle administrative processes; hazardous material security and incident response; and freight mobility.

Emergency Management holds three services — emergency notification and personal security, emergency vehicle management, and disaster response and evacuation. Advanced Vehicle Safety Systems holds seven, and is the bundle in which the connected and automated vehicle agenda sits: longitudinal collision avoidance; lateral collision avoidance; intersection collision avoidance; vision enhancement for crash avoidance; safety readiness; pre-crash restraint deployment; and automated vehicle operation. Information Management holds the single archived data function, the service that turns operational data into a planning and performance-measurement asset. Maintenance and Construction Management holds the single maintenance and construction operations service, the most recent addition to the set and the one that brings winter maintenance, fleet management and work-zone management inside the architecture.

Two qualifications belong in a complete answer. First, the architecture is a living document: ARC-IT version 8.0, issued in 2017, superseded version 7.1 by merging it with the Connected Vehicle Reference Implementation Architecture, and in doing so it replaced the eight-bundle, thirty-three-service taxonomy with a set of twelve service areas containing well over a hundred service packages. The user-service list above remains the correct answer to the question as asked, and remains the vocabulary in which most regional architectures and most funding programmes are still written, but a candidate should say that it has a successor. Second, the ITS Architecture for Canada organises essentially the same material into its own bundle set, splitting travel and traffic management into separate traveller-information and traffic-management bundles and carrying information warehousing and construction and maintenance management as bundles in their own right; a Canadian answer should name the Canadian document even when, as here, the question asks for the U.S. one.