CTE Intelligent Transportation Systems (ITS) 2

Question 1

What is 'travel time reliability' and why is it important in ITS performance measurement?

Accepted Answer

The consistency of travel times from day to day, reflecting predictability of the transportation system

Answer

Travel time reliability measures day-to-day variability in travel times; a reliable facility has consistent travel times that travelers can plan around, which FHWA measures using the Planning Time Index (PTI) and Buffer Index (BI).

Question 2

What is 'ramp metering' and what transportation benefit does it provide?

Accepted Answer

Controlling the rate at which vehicles enter a freeway on-ramp using traffic signals, to maintain mainline traffic flow

Answer

Ramp metering uses a signal at freeway on-ramps to regulate vehicle entry rates, preventing traffic demand from exceeding freeway capacity and maintaining stable flow that prevents breakdown and reduces throughput loss.

Question 3

What does 'connected vehicle' technology refer to in the context of ITS?

Accepted Answer

Vehicles equipped with wireless communication capabilities that exchange data with other vehicles, infrastructure, pedestrians, and the cloud

Answer

Connected vehicles use wireless communication (DSRC, C-V2X) to exchange data with other vehicles (V2V), infrastructure (V2I), pedestrians (V2P), and the network (V2N) to improve safety, mobility, and efficiency.

Question 4

In freeway traffic flow theory, what is the 'capacity drop' phenomenon?

Accepted Answer

The observed drop in throughput when a freeway transitions from free flow to congested breakdown conditions

Answer

Capacity drop refers to the empirically observed phenomenon where throughput at a freeway bottleneck during congested conditions is 5–15% lower than the pre-breakdown discharge rate, sustained as long as congestion persists.

Question 5

What is 'Wrong Way Driving (WWD) detection' and which ITS technology is most commonly used?

Accepted Answer

Detection of vehicles entering freeways in the wrong direction using radar, video, or thermal sensors at off-ramps, triggering alerts and DMS warnings

Answer

Wrong way driving detection systems use radar, thermal cameras, or video analytics at freeway off-ramps and interchange areas to detect wrong-way vehicle movements and immediately activate DMS, signals, and alert responders.

CTE - Certified Transportation Engineer Practice Test

CTE - Certified Transportation Engineer Practice Test

CTE Intelligent Transportation Systems (ITS) 2