CTE Intelligent Transportation Systems (ITS) 3 — Questions and Answers
Question 1: What is the primary purpose of 'incident management' programs in transportation systems?
- Investigating crash causes for liability purposes
- Detecting, responding to, and clearing traffic incidents quickly to restore normal traffic flow and reduce secondary crashes (Correct answer)
- Managing construction zone incidents and contractor disputes
- Coordinating media communications during major highway events
Correct answer: Detecting, responding to, and clearing traffic incidents quickly to restore normal traffic flow and reduce secondary crashes
Incident management programs — including Traffic Incident Management (TIM) — aim to reduce incident duration through rapid detection, quick clearance, and coordinated multi-agency response, restoring capacity and preventing secondary crashes.
Question 2: What is 'Cooperative Adaptive Cruise Control' (CACC) and how does it improve highway operations?
- Standard cruise control that adjusts speed based on posted speed limits via V2I
- A connected vehicle application allowing platoons of vehicles to travel with shorter headways by wirelessly sharing acceleration/braking data (Correct answer)
- An adaptive signal system coordinated with commercial truck routes
- A cooperative ramp metering system that adjusts rates based on freeway sensor data
Correct answer: A connected vehicle application allowing platoons of vehicles to travel with shorter headways by wirelessly sharing acceleration/braking data
CACC uses V2V communication to allow following vehicles to respond immediately to lead vehicle speed changes, enabling shorter, stable following distances (headways) and more efficient traffic flow compared to standalone ACC.
Question 3: What is the 'probe vehicle' data collection method in traffic monitoring?
- Instrumented test vehicles driven by engineers to measure pavement roughness
- Using GPS-equipped vehicles in the traffic stream (fleet vehicles, smartphones) as anonymous sensors to measure travel time and speed across the network (Correct answer)
- Police radar units used to collect spot speed data for design
- Automated vehicles programmed to drive test routes and collect sensor data
Correct answer: Using GPS-equipped vehicles in the traffic stream (fleet vehicles, smartphones) as anonymous sensors to measure travel time and speed across the network
Probe vehicle data leverages GPS-equipped vehicles — smartphones, commercial fleets, navigation apps — already traveling the network to measure real-time and historical travel times, speeds, and reliability across large geographic areas at low cost.
Question 4: What is 'managed lanes' technology and which ITS elements support their operation?
- Lanes managed by private operators under concession agreements
- Lanes with operational controls — variable tolls, occupancy requirements, or access restrictions — supported by dynamic pricing systems, enforcement cameras, and variable message signs (Correct answer)
- Lanes restricted to emergency vehicles and managed by TMC operators
- Construction zone lane management using automated flagging systems
Correct answer: Lanes with operational controls — variable tolls, occupancy requirements, or access restrictions — supported by dynamic pricing systems, enforcement cameras, and variable message signs
Managed lanes use ITS tools — dynamic pricing algorithms, RFID/transponder toll systems, video enforcement, and DMS — to adjust access pricing or restrictions in real time, maintaining reliable travel speeds for users.
Question 5: In ITS, what does 'C-V2X' stand for and how does it differ from DSRC?
- Connected Vehicle to Infrastructure exchange; it uses fiber optic cable instead of radio
- Cellular Vehicle-to-Everything; it uses LTE/5G cellular technology for V2X communication rather than dedicated DSRC spectrum (Correct answer)
- Commercial Vehicle to Exchange; it is used only for freight fleet management
- Cooperative V2X; it requires both DSRC and cellular to operate simultaneously
Correct answer: Cellular Vehicle-to-Everything; it uses LTE/5G cellular technology for V2X communication rather than dedicated DSRC spectrum
C-V2X (Cellular Vehicle-to-Everything) is an alternative V2X technology to DSRC that uses cellular networks (LTE-V2X, later 5G NR-V2X) for vehicle communications, supporting both direct device communication and network-assisted applications.
Question 6: What is the purpose of a 'Regional ITS Architecture' as required by FHWA for federally funded ITS projects?
- A detailed design drawing for all ITS equipment in a region
- A planning document defining how ITS elements in a region will work together, identifying stakeholders, services, and interfaces to guide interoperable ITS deployments (Correct answer)
- A procurement specification for regional ITS system integration contracts
- A safety certification document for autonomous vehicle testing in a region
Correct answer: A planning document defining how ITS elements in a region will work together, identifying stakeholders, services, and interfaces to guide interoperable ITS deployments
FHWA's Rule 940 requires regions to develop and maintain a Regional ITS Architecture that defines the services to be implemented, the institutional roles of stakeholders, and the interfaces between ITS elements to ensure interoperability.
CTE Intelligent Transportation Systems (ITS) 3
What is the primary purpose of 'incident management' programs in transportation systems?