Evaluation of a real-time travel time prediction system in a freeway construction work zone : executive summary.
-
2001-03-01
Details:
-
Creators:
-
Corporate Creators:
-
Subject/TRT Terms:
-
Resource Type:
-
Geographical Coverage:
-
Edition:Executive summary.
-
Corporate Publisher:
-
Abstract:A real-time travel time prediction system (TIPS) was evaluated in a construction work
zone. TIPS includes changeable message signs (CMSs) displaying the travel time and
distance to the end of the work zone to motorists. The travel times displayed by these
CMSs are computed by an intelligent traffic algorithm and travel-time estimation model
of the TIPS software, which takes input from microwave radar sensors that detect the
vehicle traffic on each lane of the freeway. Besides the CMSs and the radar sensors, the
TIPS system includes the computer and microcontroller computing the travel times,
220 MHz radios for transmitting data from the sensors to the computer and from the
computer to the CMSs, and trailers with solar panels and batteries to power the radar
sensors, CMSs, and radios. The evaluation included an accuracy analysis between the
predicted and actual recorded travel times and a survey of the motoring public. Three
crews driving independently of each other in the traffic stream recorded predicted and
actual travel times at three CMSs to the end of the work zone for 12 hours each day for
three consecutive days, resulting in 119 trial runs. The data recorder in each crew also
recorded the license plate numbers of private non-commercial vehicles with Ohio license
plates. A total of 3177 different license plate numbers were recorded and a questionnaire
was sent to each one. A total of 660 completed surveys were returned and analyzed.
Based on the regression analysis of actual times vs. predicted times, the system does on
the average a reasonable job in predicting the travel times to the end of the work zone.
About 88% of the actual times recorded for each sign, and for all the signs combined,
were within a range of ±4 minutes of the predicted time. However, a few differences
(actual-predicted) as great as 18 minutes were observed. Survey responses indicated that
the motoring public does perceive a certain inaccuracy in the travel times. However
almost 97% of surveyed motorists felt that a system to provide real-time travel time
information in advance of work zones is either outright helpful or maybe helpful. In
summary we may conclude that the real-time TIPS system represents a definite
improvement over any static non-real-time display system. It provides in general and
most of the time useful and relatively accurate travel time predictions to the motoring
public and appears to be perceived by the motoring public as a helpful addition to a
freeway construction zone.
-
Format:
-
Collection(s):
-
Main Document Checksum:
-
Download URL:
-
File Type: