1. Lec 9, Ch4, pp.115-121: Travel time and delay studies
Know how travel time and delay study results can be applied
Know definition of terms related to travel time and delay studies
Know what types of travel time studies are available
Understand how the moving-vehicle technique is conducted and its data reduced

2. What we cover in class today…
What are travel time and delay studies
How are they used?
Definition of terms
Methods requiring a test vehicle
Methods not requiring a test vehicle
Learn how to reduce data collected by the Moving-Vehicle technique

3. Travel time and delay studies
* Determines the amount of time required to travel from one point to another on a given route. Often, information may also be collected on the locations, durations, and causes of delays
Indicate the level of service
Identify problem locations

4. Applications of travel time and delay data
Many uses…
Efficiency check
Collection of rating data
Problem location identification
Model calibration
Evaluation of performance before and after improvement
Collect data for economic analysis (user costs)
See page 116

5. Definition of terms Travel time
The time taken by a vehicle to traverse a given section of a highway
Running time
The time a vehicle is actually in motion while traversing a given section of a highway
Delay
The time lost by a vehicle due to causes beyond the control of the driver
Operational delay
That part of the delay caused by the impedance of other traffic
Stopped-time delay
That part of the delay during which the vehicle is at rest
Fixed delay
That part of the delay caused by control devices such as traffic signals
Travel-time delay
The difference between the actual travel time and the travel time traversed at an average speed equal to that for an un-congested traffic flow

6. Methods Methods requiring a test vehicle: Floating-car technique
The test car “floats” with the traffic. Attempts to pass as many vehicles as those that pass the test vehicle.
Average-speed technique
Drive the test car at a speed that, in the opinion of the driver, is the average speed of the traffic streem
Moving-vehicle technique
Make a round trip on a test section and collect five pieces of information: Te, Tw, Ne, Ow, and Pw
West X Y Y X
East

7. Methods (cont) Methods not requiring a test vehicle:
License-plate observation
Each observer located at strategic points record last 3 or 4 digits of license plates. Need to synchronize the observer’s watch.
Interviews
Ask the drivers!
License-plate method  NG for a grid network – too many routes
Use of ETC for freeways

8. Moving-vehicle technique
West X Y Y X
East
Volumes
Average travel times
(Review Example 4-6)