Evaluation of a real-time travel time prediction system in a freeway construction work zone : executive summary.

Details

• Creators:
  Zwahlen, Helmut T.
• Corporate Creators:
  Ohio. Dept. of Transportation. Office of Traffic Engineering ; Ohio University
• Subject/TRT Terms:
  Route Guidance Travel Time Travel Time (Traffic Engineering)--Mathematical Models Work Zone Safety
• Resource Type:
  Tech Report
• Geographical Coverage:
  Ohio
• Edition:
  Executive summary.
• Corporate Publisher:
  Ohio. Dept. of Transportation
• 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:
  PDF
• Collection(s):
  US Transportation Collection
• Main Document Checksum:
  urn:sha256:aba7512d9543a4e92ec6bc8657726785496a44119ef35bc1dceac87bd11163c3
• Download URL:
  https://rosap.ntl.bts.gov/view/dot/17515/dot_17515_DS1.pdf
• File Type:
  [PDF - 66.00 KB ]